Mechanical pressure switches
Liquids and gases
36
DCM/DNM
Pressure switches and pressure monitors for overpressure
This universal pressure switch can be used in
general mechanical engineering and the printing
machine industry, as well as in pneumatics and
hydraulics.
SIL 2 according IEC 61508-2
DCM25
Technical data
Type
Setting range
Pressure connection
External thread G 1/2 (pressure gauge
connection) according to DIN 16 288 and internal thread G 1/4 according to ISO 228 Part 1.
Switching device
Robust housing (200) made of seawater
resistant die cast aluminium GD Al Si 12.
Protection class
IP 54, in vertical position.
Pressure sensor materials
DNM025…DCM63 Metal bellows: 1.4571
Sensor housing: 1.4104
DCM025 – DCM 1 Metal bellows: Cu Sensor
housing: Cu + Ms
DCM4016/
Diaphragm: Perbunan
DCM4025
Sensor housing: 1.4301
DCM1000
Diaphragm: Perbunan
Sensor housing: Brass
Mounting position
Vertically upright and horizontal. DCM4016
and 4025 vertically upright.
Ambient temp. at switching device
–25…+70 °C, except: DCM4016,
4025, 1000: –15…+60 °C
Max. medium temperature
The maximum medium temperature at the
pressure sensor must not exceed the
permitted ambient temperature at the
switching device. Temperatures may reach
85°C for short periods). Higher medium
temperatures are possible provided the above
limit values for the switching device are
ensured by suitable measures (e.g. siphon).
Mounting
Directly on the pressure line (pressure
gauge connection) or on a flat surface with two
4 mm Ø screws.
Switching pressure
Switching
differential
(Tolerance)
Switching differential not adjustable
DCM4016
1…16 mbar
0,7 ... 3
DCM4025
4…25 mbar
1 ... 3
DCM1000
10…100 mbar
2 ... 12
DCM025
0,04…0,25 bar
10 ... 30
DCM06
0,1…0,6 bar
10 ... 50
DCM1
0,2…1,6 bar
20 ... 60
DNM025
0,04…0,25 bar
20 ... 40
DCM3
0,2…2,5 bar
60 ... 140
DCM6
0,5…6 bar
0,14 ... 0,26
DCM625
0,5…6 bar
0,15 ... 0,35
DCM10
1…10 bar
0,2 ... 0,4
DCM16
3…16 bar
0,2 ... 0,6
DCM25
4…25 bar
0,3 ... 1,1
DCM40
8…40 bar
0,4 ... 1,6
DCM63
16…63 bar
0,6 ... 2,6
DCM63-406
40...75 bar
0,5 ... 3,0
Max.
permissible
pressure
mbar
mbar
mbar
mbar
mbar
mbar
mbar
mbar
bar
bar
bar
bar
bar
bar
bar
bar
1
1
10
6
6
6
6
16
16
25
25
25
60
60
130
130
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
6
6
6
16
16
25
25
25
60
60
130
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
Materials incontact with
medium
Perbunan
+ 1.4301
Perbunan + MS
Cu + Ms
Cu + Ms
Cu + Ms
Dimensioned
drawing
page 21 + 22
1 + 11
1 + 10
1 + 14
1 + 15
Sensor
housing
1.4104
+
Pressure
bellow
1.4571
1 + 18
1 + 17
1 + 16
Switching differential adjustable
DCMV025
DCMV06
DCMV1
DCMV3
DCMV6
DCMV625
DCMV10
DCMV16
DCMV25
DCMV40
DCMV63
0,04…0,25
0,1…0,6
0,2…1,6
0,2…2,5
0,5…6
0,5…6
1…10
3…16
4…25
8…40
16…63
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
bar
0,03…0,4
0,04…0,5
0,07…0,55
0,15…1,5
0,25…2,0
0,40…2,5
0,5…2,8
0,7…3,5
1,3…6,0
2,2…6,6
3,0…10
Cu + Ms
Sensor
housing
1.4104
+
Pressure
bellow
1.4571
1 + 14
1 + 18
1 + 17
1 + 16
Adjustable from outside with screw driver.
Switching differential
Not adjustable with DCM and types. Adjustable
from outside with DCMV types. For values see
Product Summary.
Contact arrangement
Single pole change over switch.
Switching
capacity
Normal
250 VAC 250 VDC 24 VDC
(ohm) (ind) (ohm) (ohm)
8A 5A
0.3 A
8A
For smaller pressure ranges see also VCM, DGM, HCD and DPS sheets.
For additional functions refer page 26 – 28.
Calibration
The DCM series is calibrated for falling pressure. This means that the adjustable switching pressure on
the scale corresponds to the switching point at falling pressure. The reset point is higher by the amount
of the switching differential. (See also page 23, 1. Calibration at lower switching point).
-DCM/DNM
see page 62
s
Protection Class:
IP 54
Diecast aluminium housing
IP 54 or IP 65
version also available
Wall mounting
or directly on the pressure line
Switching element (microswitch)
Lead sealable setpoint adjustment
Pressure switches
Technical features / Advantages
Pressure transmitters
Mechanical pressure switches
15
Thermostats
Mechanical pressure switches
Technical features / Advantages
Stainless steel bellows
with internal stop
Pressure connection
G 1/2" external
G 1/4" internal
Centring pin
Solenoid valves
Stainless steel sensor housing
Accessories
Terminal connection
or plug connection to
DIN EN175301 Form A
Flow monitors
Temperature sensors
Setting spindle locking element
16
Mechanical pressure switches
Definitions
Definitions
Pressure data
Overpressure
Pressure over the relevant atmospheric pressure. The reference point is
atmospheric pressure.
Vacuum
Pressure under the relevant atmospheric pressure. The reference point is
atmospheric pressure.
Absolute pressure
Overpressure relative to absolute vacuum.
Differential pressure Difference in pressure between 2 pressure measuring points.
Relative pressure
Overpressure or vacuum relative to atmospheric pressure.
Pressure data in all FEMA documents refers to relative pressure.
That is to say, it concerns pressure differentials relative to atmospheric pressure.
Overpressures have a positive sign, vacuums a negative sign.
Permissible working pressure (maximum permissible pressure)
The maximum working pressure is defined as the upper limit at which the operation, switching reliability
and water tightness are in no way impaired (for values see Product summary).
Bursting pressure (test pressure)
Type-tested products undergo a pressure test certified by TÜV affirming that the bursting pressure
reaches at least the values mentioned in the Product summary. During the pressure tests the measuring
bellows are permanently deformed, but the pressurized parts do not leak or burst. The bursting pressure
is usually a multiple of the permissible working pressure.
Setting range
Pressure range in which the cutoff pressure can be set with the setting spindle.
Pressure units
Unit
1 bar
1 mbar
bar
mbar
1
1000
10⁵
100
1
100
0.1
14.5
0.001
0.1
0.001
10-4
10-6
0.0145
1.45 · 10-4
1000
106
1
1000
0.001
1
0,145
145
1 Pa
10-5
1
0.01
1 kPa
1 MPa
0,01
10
10
104
Pa
kPa
MPa
(psi) Ib/m²
In FEMA documents pressures are stated in bar or mbar.
Pressure data for a pressure
switchbased on the example
of DWR625:
Setting range: 0.5-6 bar
Perm. working pressure: 20 bar
Bursting pressure: >100 bar
Important:
All pressure data refers to overpressures or vacuums relative to atmospheric pressure.
Overpressures have a positive sign, vacuums a negative sign.
17
Definitions
Direction of action
In principle, any pressure switch can be used for both maximum pressure and minimum pressure
monitoring. This excludes pressure limiters, whose direction of action (maximum or minimum) is
predefined. The only thing to remember is that the scale reading may deviate by the amount of the
switching differential. See example at bottom left: The scale value is 2.8 bar.
Maximum pressure monitoring
With rising pressure, switching takes place once the preset switching pressure is reached (SP).
The reset point (RSP) is lower by the amount of the switching differential.
Minimum pressure monitoring
With falling pressure, switching takes place once the preset switching pressure is reached (SP).
The reset point (RSP) is higher by the amount of the switching differential.
Direction of action in vacuum range
It is particularly important to define the direction of action in the vacuum range.
Rising does not mean a rising vacuum, but rising pressure (as viewed from absolute "0"). "Falling"
pressure means a rising vacuum.
For example: Vacuum switch set to -0.6 bar falling means: Switching (SP) takes place under falling
pressure (rising vacuum) at -0.6 bar. The reset point is higher by the amount of the switching
differential (e.g. at -0.55 bar).
Setting a pressure switch
To define the switching point of a pressure switch exactly, it is necessary to determine the direction
of action in addition to the pressure. "Rising" means that switching takes place at the set value
when the pressure rises.
The reset point is then lower by the amount of the switching differential. "Falling" means exactly
the opposite.
Pressure transmitters
Thermostats
Temperature sensors
Adjustable switching differential/ calibration
In the case of pressure switches with adjustable switching differential, the hysteresis can be set
within the specified limits. The switching point (SP) and reset point (RSP) are precisely definable.
When setting the pressure switch, the switching differential situation and the type of factory calibration must be taken into account. Some pressure switches (e.g. minimum pressure monitors of the
DCM series) are calibrated under "falling" pressure, i.e. switching under falling pressure takes place
at the scale value with the switching differential being above it. The device switches back at scale
value + switching differential. If the pressure switch is calibrated under rising pressure, switching
takes place at the scale value and the device switches back at scale value - switching differential
(see direction of action). The calibration method is indicated in the data sheets.
Flow monitors
The switching differential (hysteresis) is the difference in pressure between the switching point
(SP) and the reset point (RSP) of a pressure switch. Switching differential tolerances occur due to
tolerances in the microswitches, springs and pressure bellows. Therefore the data in the product
summaries always refers to average values. In the case of limiter functions the switching differential
has no significance, as one is only interested in the switching point at which cutoff occurs, not the
reset point. For a controller function, i. e. in the case of pressure switches used to switch a burner, pump etc. on and off, a pressure switch with an adjustable switching differential should be
chosen. The switching frequency of the burner or pump can be varied by changing the switching
differential.
Solenoid valves
Minimum pressure monitoring
RSP = SP + xd
Switching differential
Please note when specifying the setting of a pressure switch:
In addition to the switching point it is also necessary to specify the direction of action
(falling or rising).
Example for selection of a pressure switch:
A pump is to be turned on at 2.8 bar and off again at 4.2 bar.
Chosen type: DCMV6 according to data sheet DCM. Setting: Scale pointer to 2.8 bar
(lower switching point). Switching differential to 1.4 bar (set according to pressure gauge).
Cutoff point: 2.8 bar +1.4 bar = 4.2 bar.
Accessories
Maximum pressure monitoring
RSP = SP – xd
Pressure switches
Mechanical pressure switches
Definitions
Mechanical pressure switches
General description
18
Operating mode
The pressure prevailing in the sensor housing (1) acts on the measuring bellows (2). Changes in
pressure lead to movements of the measuring bellows (2) which are transmitted via a thrust pin
(4) to the connecting bridge (5). The connecting bridge is frictionlessly mounted on hardened points
(6). When the pressure rises the connecting bridge (5) moves upwards and operates the microswitch
(7). A counter-force is provided by the spring (8), whose pre-tension can be modified by the adjusting
screw (9) (switching point adjustment). Turning the setting spindle (9) moves the running nut (10) and
modifies the pre-tension of the spring (8). The screw (11) is used to calibrate the microswitch in the
factory. The counter pressure spring (12) ensures stable switching behaviour, even at low setting values.
1
2
3
4
5
6
7
=
=
=
=
=
=
=
8 =
9 =
10 =
11 =
12 =
Pressure connection
Measuring bellows
Sensor housing
Thrust pin
Connecting bridge
Pivot points
Microswitch or other
switching elements
Setting spring
Setting spindle (switching
point adjustment)
Running nut (switching point
indicator)
Microswitch calibration
screw (factory calibration)
Counter pressure spring
Pressure sensors
Apart from a few exceptions in the low-pressure range, all pressure sensors have measuring bellows,
some made of copper alloy, but the majority of high-quality stainless steel. Measured on the basis of
permitted values, the measuring bellows are exposed to a minimal load and perform only a small lifting
movement. This results in a long service life with little switching point drift and high operating reliability.
Furthermore, the stroke of the bellows is limited by an internal stop so that the forces resulting from
the overpressure cannot be transmitted to the switching device. The parts of the sensor in contact with
the medium are welded together without filler metals. The sensors contain no seals. Copper bellows,
which are used only for low pressure ranges, are soldered to the sensor housing. The sensor housing
and all parts of the sensor in contact with the medium can also be made entirely from stainless steel
1.4571 (DNS series). Precise material data can be found in the individual data sheets.
Pressure connection
The pressure connection on all pressure switches is executed in accordance with DIN 16288 (pressure
gauge connection G 1/2A). If desired, the connection can also be made with a G 1/4 internal thread in
accordance with ISO 228 Part 1.
Maximum screw-in depth on the G 1/4 internal thread = 9 mm.
Centring pin
In the case of connection to the G 1/2 external thread with seal in the thread (i.e. without the usual
stationary seal on the pressure gauge connection), the accompanying centring pin is not needed.
Differential pressure switches have 2 pressure connections (max. and min.), each of which are to be
connected to a G 1/4 internal thread.
…200
Switch housing
Die cast aluminium GDAISi 12
Pressure connection
…300
Die cast aluminium GDAISi 12
G 1/2" external thread (pressure gauge
connection) and G 1/4" internal thread.
1/4" internal thread for DDCM differential
pressure switches
Switching function and Floating changeover contact.
connection scheme
With rising pressure
(applies only to version with single pole switching
microswitch)
from 3–1 to 3–2.
Switching capacity
8 A at 250 VAC
(for microswitches with
5 A at 250 VAC inductive
a silver contact)
8 A at 24 VDC
0.2 A at 110 VDC
0.3 A at 250 VDC
min. 10 mA, 12 VDC
G 1/2" external thread (pressure gauge
connection) and G 1/4" internal thread.
1/4" internal thread for DDCM differential
pressure switches
Floating changeover contact.
With rising pressure
single pole switching
from 3–1 to 3–2
8 A at 250 VAC
5 A at 250 VAC inductive
8 A at 24 VDC
0.2 A at 110 VDC
0.3 A at 250 VDC
min. 10 mA, 12 VDC
Mounting position
Preferably vertical (see technical data sheet)
Preferably vertical (see technical data sheet)
Protection class
(in vertical position)
IP 54
IP 65
Electrical connection
Plug connection
Terminal connection
Cabel entry
Pg 11
M 16 x 1.5
Ambient temperature
–25 to +70 °C (exceptions:
DWAM, DWAMV, SDBAM series –20 to +70 °C
DGM and FD series: –25 to +60 °C
DCM4016, 4025, 1000,
VCM4156: –15 to +60 °C)
–25 to +70 °C (exceptions:
DWAM, DWAMV, SDBAM series –20 to +70 °C
DGM and FD series: –25 to +60 °C
DCM4016, 4025, 1000,
VCM4156: –15 to +60 °C)
Switching point
Adjustable using the setting spindle
Adjustable using the setting spindle once the
switch housing cover is removed
Hysteresis
Adjustable or not adjustable
(see Product Summary)
Adjustable or not adjustable
(see Product Summary)
Medium temperature
Max. 70 °C, briefly 85 °C
Max. 70 °C, briefly 85 °C
Relative humidity
15 to 95% (non-condensing)
15 to 95% (non-condensing)
Vacuum
Higher medium temperatures are possible provided the above limits for the switching device are
ensured by suitable measures (e.g. siphon). All pressure switches can operate under vacuum.
This will not damage the device (exception DCM1000).
< 1 % of the working range (for pressure ranges > 1 bar).
Repetition accuracy
of switching points
Vibration resistance
No significant deviations up to 4 g.
Mechanical durability
(pressure sensor)
With sinusoidal pressure application and room temperature, 10 x 106 switching cycles. The expected
life depends to a very large extent on the type of pressure application, therefore this figure can serve
only as a rough estimate. With pulsating pressure or pressure impacts in hydraulic
systems, pressure surge reduction is recommended.
100.000 switching cycles at nominal current 8 A, 250 VAC.
A reduced contact load increases the number of possible switching cycles.
Overvoltage category III, contamination class 3, reference surge voltage 4000 V.
Conformity to DIN VDE 0110 is confirmed.
The parts of all pressure switches in contact with the medium are oil and grease free
(except the HCD…and DPS…series). The sensors are hermetically sealed and contain no seals
(also see ZF1979, special packing).
Electronical durability
(microswitch)
Isolation values
Oil and grease-free
Pressure switches
Pressure transmitters
Terminal connection
Thermostats
Standard version
Plug connection
Temperature sensors
Valid for all pressure switches of the DCM, DNM, DWAM, DWAMV, SDBAM, VCM, VNM, DNM, DWR, DGM,
DNS and DDCM series that have a microswitch. The technical data of type tested units may differ slightly
(please refer to particular type sheet).
Flow monitors
Principal technical data
Solenoid valves
19
Accessories
Mechanical pressure switches
Principal technical data
Mechanical pressure switches
Principal technical data
20
Principal technical data
Valid for all pressure of the DCM, VCM, VNM, DNM, DWR, DGM, DNS, DWAM, DWAMV and DDCM series that
have a microswitch. The technical data of type-tested units may differ slightly (please refer to particular type sheet).
Ex-i-version
version (Ex-d)
…500
…700
Switch housing
Die cast aluminium GDAISi 12
Die cast aluminium GDAISi 12
Pressure connection
G 1/2" external thread (pressure gauge
connection) and G 1/4" internal thread.
1/4" internal thread for DDCM differential
pressure switches
Floating changeover contact.
With rising pressure
single pole switching
from 3–1 to 3–2
max.: 100mA, 24VDC
min.: 2mA, 5VDC
Mounting position
Vertical
G 1/2" external thread (pressure gauge connection)
and G 1/4" internal thread.
1/4" internal thread for DDCM differential pressure
switches
Floating changeover contact.
With rising pressure
single pole switching
from 3–1 to 3–2
3 A at 250 VAC
2 A at 250 VAC inductive
3 A at 24 VDC
0.1 A at 250 VDC
min. 2 mA, 24 VDC
Vertical
Protection class
(in vertical position)
Explosion protection
Code
EC Type Examination
Certificate Number
Electrical connection
IP 65
IP 65
II 1/2G Ex ia IIC T6 Ga/Gb
II 1/2D Ex ia IIIC T80 °C
IBExU12ATEX1040
II 2G Ex d e IIC T6 Gb
II 1/2D Ex ta/tb IIIC T80 °C Da/Db
IBExU12ATEX1040
Terminal connection
Terminal connection
Cabel entry
M 16 x 1.5
M 16 x 1.5
Ambient temperature
–20 to +60 °C
Medium temperature
–25 to +60 °C (exceptions:
DWAM series –20 to +60 °C
DGM and FD series: –25 to +60 °C
DCM4016, 4025, 1000, VCM4156: –15 to +60 °C)
Max. 60 °C
Relative humidity
15 to 95% (non-condensing)
15 to 95% (non-condensing)
Switching point
After removing switch housing cover
After removing switch housing cover
Hysteresis
Not adjustable
Not adjustable
Vacuum
Higher medium temperatures are possible provided the above limits for the switching device are
ensured by suitable measures (e.g. siphon). All pressure switches can operate under vacuum.
This will not damage the device.
< 1 % of the working range (for pressure ranges > 1 bar).
Switching function and
connection scheme
(applies only to version
with microswitch)
Switching capacity
Repetition accuracy
of switching points
Max. 60 °C
Vibration resistance
No significant deviations up to 4 g.
Mechanical durability
(pressure sensor)
With sinusoidal pressure application and room temperature, 10 x 106 switching cycles. The expected life
depends to a very large extent on the type of pressure application, therefore this figure can serve only as a
rough estimate. With pulsating pressure or pressure impacts in hydraulic systems, pressure surge reduction is
recommended.
100.000 switching cycles at nominal current 8 A, 250 VAC.
A reduced contact load increases the number of possible switching cycles.
Electronical durability
(microswitch)
Isolation values
Oil and grease-free
Overvoltage category III, contamination class 3, reference surge voltage 4000 V.
Conformity to DIN VDE 0110 is confirmed.
The parts of all pressure switches in contact with the medium are oil and grease free
(except the HCD…and DPS…series). The sensors are hermetically sealed and contain no seals
(also see ZF1979, special packing).
21
Dimensioned drawings of switch housings (mm)
102.6
72
46
DIN EN 175301
48.5
45.5
37
8.2
4.8
60
46±0.2
Housing 300 (terminal connection)
2
112
Pressure transmitters
Housing 200 (plug connection)
1
Thermostats
33.5
32.5
8.2
45
56
67
4.8
Pg11
Pressure switches
Mechanical pressure switches
Dimensioned drawings
4
Housing 500 (terminal connection Ex-i)
Housing 700 (terminal connection Ex-d)
102.6
102.6
72
46
72
46
11.1
4.8
33.5
8.2
Flow monitors
42.3
32.5
76.5
76.5
56
8.2
45
33.5
32.5
56
42.3
76.5
76.5
4.8
45
3
Temperature sensors
60±0.1
60±0.1
Dimensioned drawings of pressure sensors (mm)
10
11
Solenoid valves
60±0.1
G1/4
20
SW22
Ø6
G1/4
G1/2
132
Accessories
6
3.5
3.5
26
20
G1/2A
56
36.5
SW24
Mechanical pressure switches
Dimensioned drawings
22
Dimensioned drawings of pressure sensors (mm)
13
2
12
64
69
82
Ø
20
hex22
3.5
20
30
SW22
Ø6
G1/4
G1/2
G1/4
G1/2
14
15
61
50
he41
20
3.5
3.5
20
hex22
Ø6
G1/4
G1/2
Ø6
G1/4
G1/2
16
19
3.5
20
55
hex
Dimensioned
drawing
hex
(mm)
16
17
18
19
22
24
30
32
Ø6
G1/4
G1/2
20
21
G1/4
90
44
21
74
40
G1/4
11max
hex 41
70
102
In view of tolerances in the characteristics of sensors and springs, and due to friction in the switching
kinematics, slight discrepancies between the setting value and the switching point are unavoidable.
The pressure switches are therefore calibrated in the factory in such a way that the setpoint
adjustment and the actual switching pressure correspond as closely as possible in the middle of
the range. Possible deviations are equally distributed on both sides.
The device is calibrated either for falling pressure (calibration at lower switching point) or for rising
pressure (calibration at higher switching point), depending on the principal application of the type
series in question.
Where the pressure switch is used at other than the basic calibration, the actual switching point
moves relative to the set switching point by the value of the average switching differential. As FEMA
pressure switches have very small switching differentials, the customer can ignore this where the
switching pressure is set only roughly. If a very precise switching point is needed, this must be
calibrated and checked in accordance with normal practice using a pressure gauge.
1. Calibration at lower switching point
Setpoint xS corresponds to the lower switching
point, the upper switching point xO is higher
by the amount of the switching differential xd.
2. Calibration at upper switching point
Setpoint xS corresponds to the upper switching
point, the lower switching point xU is lower
by the amount of the switching differential xd.
The chosen calibration type is indicated in the technical data for the relevant type series.
Flow monitors
Prior to adjustment, the securing pin above the scale must be loosened by not more than 2 turns and
retightened after setting. The switching pressure is set via the spindle. The set switching pressure is
shown by the scale.
To set the switching points accurately it is necessary to use a pressure gauge.
Direction of action of setting
spindle
Clockwise:
greater difference
Anticlockwise:
smaller difference
With pressure switches from
the DWAMV and DWR...-203
series, the direction of action of
the differential screw is
reversed.
C h a n g i n g t h e s w i t c h i n g d i f f e r e n t i a l (only for switching device with suffix "V", ZF203)
By means of setscrew within the spindle. The lower switching point is not changed by the
differential adjustment; only the upper switching point is shifted by the differential. One turn of
the differential screw changes the switching differential by about 1/4 of the total differential range. The
switching differential is the hysteresis, i.e. the difference in pressure between the switching point and
the reset point.
Solenoid valves
Anticlockwise:
higher switching
pressure
Setting switching pressures
L e a d s e a l i n g o f s e t t i n g s p i n d l e (for plug connection housing 200 only)
The setting spindle for setting the desired value and switching differential can be covered and
sealed with sealing parts available as accessories (type designation: P2) consisting of a seal plate
and capstan screw. The sealing parts may be fitted subsequently. The painted calibration screws
are likewise covered.
Accessories
Clockwise:
lower switching
pressure
Pressure switches
Factory calibration of pressure switches
Pressure transmitters
Setting instructions
Thermostats
23
Temperature sensors
Mechanical pressure switches
Setting instructions
24
Mechanical pressure switches
Pressure switch with locking of switching state (reclosing lockout)
Pressure switch with switching state
locking (reclosing lock out)
In the case of limiter functions, the switching state must be retained and locked, and it may be unlocked
and the system restarted only after the cause of the safety shutdown has been eliminated. There are two
ways of doing this:
1. Mechanical locking inside the pressure switch
Instead of a microswitch with automatic reset, limiters contain a "bi-stable" microswitch. If the pressure
reaches the value set on the scale, the microswitch trips over and remains in this position. The lock can
be released by pressing the unlocking button (identified by a red dot on the scale side of the switching
device). The lock can operate with rising or falling pressure, depending on the version. The device can
only be unlocked when the pressure has been reduced (or increased) by the amount of the
predefined switching differential. When selecting a pressure limiter, it is necessary to distinguish
between maximum and minimum pressure monitoring. Ex-d versions cannot be equipped with internal
locking.
Maximum pressure limitation
Minimum pressure limitation
Switching and interlocking with rising pressure.
Additional function
ZF205.
Switching and interlocking
with falling pressure.
Additional function
ZF206.
Connection of control
current circuit to
terminals 1 and 3.
Connection of control
current circuit to
terminals 2 and 3.
2. External electrical interlock in the control cabinet (suggested circuits)
A pressure monitor (microswitch with automatic reset) can also be used as a limiter if an electrical
interlock is added. For pressure limitation in steam and hot water boilers, an external interlock is only
permitted if it has been ascertained that the pressure monitor is "of special construction".
Maximum pressure limitation
with external interlock
Minimum pressure limitation
with external interlock
Where the above lock circuit is used, the requirements of DIN 57 116/VDE 0116 are met if the electrical
equipment (such as contactors or relays) of the external interlock circuit satisfy VDE 0660 or VDE 0435.
Explanation of type designations –
type codes
The type designations of FEMA pressure switches consist of a combination of letters followed by a
number denoting the setting range. Additional functions and version variants are indicated by an extra
code which is separated from the basic type by a hyphen. Ex-versions (explosion protection Ex-d)
are identified by the prefix "Ex" in front of the type designation.
With additional function
Ex-version
DCMXXX-YYY
Ex-DCMXXX
DCM
XXX
Series code (e. g. DCM)
Codes for pressure range
YYY
Ex
Code for additional function
Code for Ex-version
Thermostats
Basic version
(based on the example of DCM series)
DCMXXX
Terminal connection housing (300)
Ex-DCMXXX
DCMXXX-5…
Ex-d switching device (700)
Ex-i version (500)
Which additional function fits with which pressure switch?
Plug connection, 200 series
Terminal connection, 300/500 series
Additional function ZF
Additional function ZF
213
217
•1
•
•
•
•
•
•
•
•1
•
DCM/VCM
VNM/DNS/VNS
DWAM
DDCM
DWR
DGM
• available
•
1
301
351
•
•
•
•
•
•
307
513
•1
•
•
•
•
•
•
•
574
575
576
577
Flow monitors
DCMXXX-3…
•
•
•
except DCM4016, DCM4025, VCM4156 and DCM1000
Combination of several additional functions is not possible!
Ex-versions (Ex-d) can only be supplied in basic form.
Additional functions are not possible.
Note to non-available items:
In our article master all the possible technical combinations are not created.
Therefore we recommend the previous request for clarification and selection of
an alternative solution.
•
•
Solenoid valves
Basic version with plug connection housing
Basic version with plug connection housing
Accessories
DCMXXX
DCMXXX-2…
Temperature sensors
Switch housing version
203
Pressure switches
25
Pressure transmitters
Mechanical pressure switches
Explanation of type designations – type codes
26
Mechanical pressure switches
Additonal functions / Connecting schemes
Pressure switches and pressure monitors
Additional functions / Connection schemes
Plug connection,
200 series (IP 54)
Terminal connection,
300 series (IP 65)
Connection scheme
Standard version
(plug connection)
Micro switch, single pole
switching, switching
differential not adjustable
Terminal connection
housing (300)
ZF301
Unit with adjustable
switching differential
ZF203
Maximum pressure limiter
with reclosing lockout
Interlocking with
rising pressure
see DWR series
ZF205
Minimum pressure limiter
with reclosing lockout
Interlocking with
falling pressure
see DWR series
ZF206
Note to non-available items:
In our article master all the possible technical combinations are not created. Therefore we recommend
the previous request for clarification and selection of an alternative solution.
Thermostats
Two micro switches, 1 plug
switching in succession,
no adjustable switching
differential.
State the switching
scheme * (not possible
with all pressure switches).
ZF307
ZF217 *
Gold-plated silver contact,
single pole switching (not
available with adjustable
switching differential).
Temperature sensors
Connection scheme
selection, see page 32
ZF213
Switching capacity:
max. 24 VDC, 100 mA,
min. 5 VDC, 2 mA
ZF351
Flow monitors
Switch housing with
surface protection
(chemical version)
Note to non-available items:
In our article master all the possible technical combinations are not created. Therefore we recommend
the previous request for clarification and selection of an alternative solution.
* Connection schemes for switching schemes, see page 32.
Please state interval when ordering!
Example for ordering: DCM10-217A-S.
Additional text: switching scheme A4
Example for ordering:
DCM 6 – 205
Code of additional function
(e.g. maximum limiter)
Code for pressure range
Sensor system
How to order:
Pressure switch
DCM6-205
or DCM6 with ZF205
Solenoid valves
Two micro switches, switching
in parallel or in succession. Fixed
switching differential, only
possible with terminal
connection housing.
State the switching differential
(not possible with all pressure
switches).
Pressure transmitters
Terminal connection Connection scheme
300 series (IP 65)
Accessories
Plug connection
200 series (IP 54)
27
Pressure switches
Mechanical pressure switches
Additonal functions / Connecting schemes
Mechanical pressure switches
Additonal functions / Connecting schemes
28
Pressure switches and pressure monitors
Additional functions for Ex-i-equipment
· Housing (500) with terminal connection (IP 65), "blue" cable entry and terminals.
· Also available with resistor combination for line break and short-circuit monitoring (with isolating amplifier).
! Important:
All pressure switches with the ZF5… additional functions listed here can only be operated in combination with
a suitable isolating amplifier.
DWAM6-576
i Additional information:
Our pressure switches and thermostats are considered to be "simple electrical equipment" within the meaning
of standard EN60079-11: 2007. Testing is not mandatory for this type of equipment.
Additional functions for Ex-equipment
Gold plated contact
single pole switching, fixed hysteresis,
not adjustable
Switching capacity:
max. 24 VDC, 100 mA, min. 5 VDC, 2 mA
For the power supply circuit:
Ui 24 V DC
Ci
1 nF
Ii
100 mA
Li
100 µH
Connection scheme
ZF513
Versions with resistor combination for line break and short-circuit monitoring in control current circuit, ZF574 – ZF577
see DBS series, pages 50 – 52:
For
Ui
Ri
Ci
Li
the power supply circuit:
14 V DC
1500 Ohm
1 nF
100 µH
Normally closed contact with resistor
combination, for minimum pressure
monitoring, gold plated contact,
plastic-coated housing (chemical version).
ZF574
Normally closed contact with reclosing
lockout and resistor combination,
for minimum pressure monitoring,
plastic coated housing (chemical version).
ZF575
Normally closed contact with resistor
combination, for maximum pressure
monitoring, gold plated contact,
plastic coated housing (chemical version).
ZF576
Normally closed contact with reclosing
lockout and resistor combination,
for maximum pressure monitoring,
plastic-coated housing (chemical version).
ZF577
Note to non available items:
In our article master all the possible technical combinations are not created. Therefore we recommend
the previous request for clarification and selection of an alternative solution.
Devices with service functions will be produced according to the customer’s specifications.
The system requires that these product combinations are identified in such a way as to prevent any possibility
of confusion. These combinations are characterised by a product code with the suffix "-S" on the packaging
label as well as separate labels with barcodes for each service function.
Service functions
Adjustment according to customer’s instruction:
- one switching point
- two switching points or defined switching differential
Plug connection
Terminal connection
Ex-i/
200 series
300 series
Ex-d
ZF1970*
ZF1970*
ZF1970*
ZF1972*
ZF1972*
–
–
–
ZF1973*
–
–
ZF1978
ZF1978
ZF1978
ZF1979
ZF1979
ZF1979
WZ2.2
WZ2.2
WZ2.2
AZ3.1B1
AZ3.1-V
AZ3.1B1
AZ3.1-V
AZ3.1B1
AZ3.1-V
Adjustment and lead sealing according to customer’s instruction:
ZF1971*
- one switching point
- two switching points or defined switching differential
Labelling of units according to customer‘s
instruction with sticker
Special packing for oil and grease-free storage
Test reports according to EN 10 204
- Certificate 2.2 based on non specific specimen test
- Inspection test certificate 3.1 based on specific test
- Inspection test certificate for FV separating diaphragms
Pressure switches
Service functions
Pressure transmitters
29
Thermostats
Mechanical pressure switches
Service functions
Included items: Labels with barcodes on the packaging:
DCM6-S
ZF1970: set to 4 bar rising
ZF1978: PSH008
AZ3.1B1
Pack contents: 1
1
1
1
1
DCM6 (without "S" suffix) marked
ZF1970: set to 4 bar rising
ZF1978: PSH008
AZ3.1 B1 will be sent by extra post
Installation and operating instructions
Flow monitors
Example:
Ordering 1 DCM6, set at 4 bar rising, identified with code PSH008 as requested by the customer and acceptance test certificate 3.1.
The order confirmation contains:
1 DCM6-S ("S" is need for factory = following lines belong to this item)
1 ZF1970: set to 4 bar rising
1 ZF1978: PSH008
1 AZ3.1B1
Solenoid valves
Ordering devices with service functions
Accessories
Service functions are available for the following type series (including Ex-versions):
Pressure switches: DCM, DNM, DNS, VNS, VCM, VNM, DDCM, DWR, DWAM, DWAMV, SDBAM, DGM, FD
Temperature sensors
* Switching point adjustment: Please specify switching point and direction of action (rising or falling pressure).
30
Mechanical pressure switches
S2 type series
S2 type series
Pressure switches with 2 microswitches - technical data
FEMA pressure switches of the DCM (except
DCM1000, DCM4016 and DCM4025), VCM
(except VCM4156), VNM series can be equipped with 2 microswitches.
Technical data
Standard equipment
The standard equipment of every two stage
pressure switch includes a switching device
with 2 microswitches, both single pole
switching. Switch I monitors the low pressure,
switch II the higher pressure. The setting
ranges indicated in the data sheets for the
basic types apply to the two stage pressure
switches as well. It should be noted that the
switching differentials of the individual microswitches may not be exactly the same due to
component tolerances.
Switching difference (see table, page
31)
The switching interval of the two microswitches
is the difference (in bar or mbar) between the
switching points of the two micro switches.
This is not possible with any other type
series or with Ex-versions.
The applicable data sheet for the basic types contains the technical data for the two stage pressure switches. This includes all limits of use, such as temperature, maximum pressure, mounting position, protection class, electrical data etc. The principal dimensions are the same as for single-stage
pressure switches with comparable pressure ranges and design features.
Additional Switching difference
function
between the two
micro switches
Factory setting
ZF307
according to
customer’s
instruction
Switching difference
fixed
Electrical
connection
Connection
diagram
Ordering
information required
Terminal
connection
(All terminals
of both
microswitches
are accessible
(6 terminals)
2 x single pole
switching
1. Basic type with ZF307
2. Switching points I
and II, with direction
of action in each
case (rising or falling
pressure)
Example: DCM16-307
Switching point I:
10 bar falling
Switching point II:
12 bar falling or
switching interval only.
Plug connection
in accordance with
DIN EN175301
(3-prong + earth
conductor)
Functionappropriate
internal wiring in
accordance with
"Switching
functions" table
Example selection
in accordance
with "Switching
schemes" table,
page 32.
1. Basic type with
ZF217
2. Switching scheme
For example:
DCM16-217/B 4
Since all values are
adjustable within the
specified limits, no
further data is required.
Example for ZF307:
When the pressure rises (e.g. 2.8 bar), a
two stage pressure switch turns on a warning
light, and if the pressure continues to rise (e.g.
3.2 bar) the system shuts down. The switching
interval is 3.2-2.8 = 0.4 bar. The following
applies to all versions:
The switching interval remains constant over
the whole setting range of the pressure switch.
If the switching pressure setting is changed
with the setting spindle, the switching interval
does not change - the switching points are
moved in parallel.
ZF217
Switching differential (see table page
31)
Adjustable
via adjustment
knobs I and II in
accordance with
"Switching
difference" table
The switching differential, i.e. the hysteresis of
the individual micro switches, corresponds to
the values of the relevant basic version referred
to in the Product summary. In the case of
two stage pressure switches, the switching
differential of the individual micro switches
is not adjustable.
Versions
Two stage pressure switches are available in
three different versions, each identified by a ZF
number. The versions differ in terms of their
connection schemes and electrical connection
types (terminal or plug connection).
Note on ordering additional function ZF217
Switching scheme
Switching device
Ordering position
Additional text
A1
A2
A3
A4
B1
B2
B3
B4
C1
C2
C3
C4
D1
D2
D3
D4
A
C
C
A
B
D
D
B
B
D
D
B
A
C
C
A
DCM6-217A-S
DCM6-217C-S
DCM6-217C-S
DCM6-217A-S
DCM6-217B-S
DCM6-217D-S
DCM6-217D-S
DCM6-217B-S
DCM6-217B-S
DCM6-217D-S
DCM6-217D-S
DCM6-217B-S
DCM6-217A-S
DCM6-217C-S
DCM6-217C-S
DCM6-217A-S
Switching scheme A1
Switching scheme A2
Switching scheme A3
Switching scheme A4
Switching scheme B1
Switching scheme B2
Switching scheme B3
Switching scheme B4
Switching scheme C1
Switching scheme C2
Switching scheme C3
Switching scheme C4
Switching scheme D1
Switching scheme D2
Switching scheme D3
Switching scheme D4
Switching difference of two stage pressure switches (ZF217, ZF307)
Type series
S2
ZF217
ZF307
40
20
40
0,1
0,15
0,25
0,3
0,6
0,9
1,3
35
40
40
20
50
mbar
mbar
mbar
bar
bar
bar
bar
bar
bar
bar
mbar
mbar
mbar
mbar
mbar
max. switching difference (mean values) (ZF217,ZF307)
switching
scheme
A1/A3/B2/B4
C1/C3/D2/D4
+ ZF 307
165
140
240
0,65
0,95
1,6
2,0
4,0
6,0
8,5
215
300
260
100
310
mbar
mbar
mbar
bar
bar
bar
bar
bar
bar
bar
mbar
mbar
mbar
mbar
mbar
switching scheme switching scheme
A2/A4/C2/C4
B1/B3/D1/D3
190mbar
160mbar
280mbar
0,75bar
1,2bar
1,85bar
2,3bar
4,6bar
6,9bar
9,8bar
240mbar
340mbar
300mbar
120mbar
360mbar
140mbar
120mbar
200mbar
0,55bar
0,8bar
1,35bar
1,7bar
3,4bar
5,1bar
7,2bar
180mbar
260mbar
220mbar
80mbar
260mbar
Additional function ZF217
On switching devices with additional function ZF217, the switching differene is continuously
adjustable via two adjustment knobs I and II accessible from outside. The maximum possible
switching difference is stated in the "Switching difference" table.
Turning adjustment knob I clockwise produces a lower switching point for microswitch I
Turning adjustment knob II anticlockwise produces a higher switching point for microswitch II
Adjustment knobs I and II have an internal stop to prevent the micro switches from being adjusted
beyond the effective range.
Adding together the adjustments on knobs I and II results in the switching difference between the
two micro switches. Changes made with the setting spindle do not affect the switching difference.
The switching difference remains constant over the whole setting range of the spindle. The two
switching points are moved up or down in parallel.
Recommended adjustment method for switching devices with ZF217
1. Set adjustment knobs I and II
to their basic positions.
Turn adjustment knob I
anticlockwise as far as possible.
Turn adjustment knob II
clockwise as far as possible.
2. Adjust the setting spindle S by the scale to a value midway between the desired upper and
lower switching points.
3. With pressure applied, set the lower switching point with adjustment knob I.
4. In the same way as in step 3, set the upper switching point with adjustment knob II.
5. If the desired upper and lower switching points cannot be reached, turn the setting spindle S in
the appropriate direction and repeat steps 3 and 4.
Flow monitors
Switching devices with adjustable switching difference
Solenoid valves
DCM06
DCM025
DCM1
DCM3
DCM6
DCM10
DCM16
DCM25
DCM40
DCM63
DNM025
VCM095
VCM101
VCM301
VNM111
Lower pressure
Accessories
Type
Higher pressure
min. switching difference
(ZF217)
Factory default (parallel)
ZF307
Pressure switches
ZF217 and ZF307 pressure switches with two microswitches
and switching difference
Pressure transmitters
S2 type series (selection)
Thermostats
31
Temperature sensors
Mechanical pressure switches
S2 type series
Mechanical pressure switches
S2 type series
32
S2 type series
Two stage pressure switches, switching schemes for ZF217
Function appropriate internal configuration of microswitches I and II, switching scheme selection table. The switch position shown
corresponds to the pressureless state. On the horizontal axis is the switching function of microswitch I (A–D); on the vertical axis is the
switching function of microswitch II (1–4). At the intersection is the switching scheme which satisfies both conditions (e.g. A 2).
Microswitch I (lower switching point)
rising, close
falling, open
rising, open
rising, close
falling, open
rising, open
Microswitch II (upper switching point)
falling, close
falling, close
Information required when ordering:
As well as the basic type (e.g. DCM10) and the switching scheme (e.g. A 2), for factory setting it is
also necessary to indicate the switching points and direction of action:
Example: DCM10-217C-S, switching scheme: A2, Switch I: 6.5 bar falling, Switch II: 7.5 bar rising.
Example 1:
Requirement
Pressure holding devices and automatic expansion valves usually have a gas cushion whose
pressure must be kept constant within a certain range. If the pressure is too low, a compressor is
switched on. If the pressure is too high, a solenoid valve must be opened to vent the gas. Between
these two levels is a neutral zone, in which the compressor and the solenoid valve are at rest.
Solution
All pressure switches of types DCM each with additional function ZF217 and switching scheme A 2,
are suitable. All pressure ranges listed in the technical documents are possible. Example for ordering: see page 32
Switching function / connection scheme
Switch I:
With falling pressure, contact 1–2 closes (compressor on)
With rising pressure, contact 1–2 opens (compressor off)
Switch II:
Minimum and maximum pressure monitoring in a nitrogen line
With rising pressure, contact 2–3 closes (valve open)
With falling pressure, contact 2–3 opens (valve closed).
In between there is a neutral zone in which the compressor is not switched
on and the solenoid coil is not energized (off position).
Example 2:
Requirement
In a process engineering system, the pressure in a nitrogen line has to be monitored. A green signal
lamp indicates that the pressure in the line is between 2.2 and 2.6 bar. If the pressure goes below
2.2 bar or above 2.6 bar, the indicator lamp goes out and the system shuts down.
Solution
The first contact of a DCM3–307 pressure switch with 2 microswitches opens under falling pressure
at 2.2 bar; the second microswitch opens under rising pressure at 2.6 bar. If the pressure is >2.2
bar or
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