Isolated Analog Signal Conditioning Products
S C M 5 B
SCM5B34
Linearized 2- or 3-Wire RTD Input Modules
Description
Each SCM5B34 RTD input module provides a single channel of RTD
input which is filtered, isolated, amplified, lineari ed, and converted to a
high-level analog voltage output (Figure 1). This voltage output is logic
switch controlled, which allows these modules to share a common analog
bus without the re uirement of external multiplexers.
The SCM5B modules are designed with a completely isolated computer
side circuit which can be oated to
from Power ommon, pin .
This complete isolation means that no connection is re uired between I O
Common and Power Common for proper operation of the output switch.
If desired, the output switch can be turned on continuously by simply
connecting pin , the Read nable pin, to I O ommon, pin .
RTD excitation is provided from the module by two matched current
sources. When using a three-wire RTD, this method allows an equal
current to ow in each RTD lead, which cancels the effects of lead
resistances. The excitation currents are very small . mA for
Pt and
Ni, and . mA for
u which minimi es self heating of the RTD.
Signal filtering is accomplished with a six pole filter which provides
95dB of normal-mode rejection at 60Hz and 90dB at 50Hz. Two poles
of this filter are on the field side of the isolation barrier, and the other
four are on the computer side. After the initial field side filtering, the input
signal is chopped by a proprietary chopper circuit. Isolation is provided by
transformer coupling, again using a proprietary technique to suppress
transmission of common mode spikes or surges. The module is powered
from +5VDC, ± 5%.
Features
Interfaces to
Platinum,
or
Nic el RTDs
• Linearizes RTD Signal
• High-Level Voltage Outputs
• 1500Vrms Transformer Isolation
• ANSI/IEEE C37.90.1 Transient Protection
• Input Protected to 240VAC Continuous
• 160dB CMR
• 95dB NMR at 60Hz, 90dB at 50Hz
SA
S ertified
• CE and ATEX Compliant
• Mix and Match SCM5B Types on Backpanel
A special input circuit on the SCM5B34 modules provides protection
against accidental connection of power-line voltages up to 240VAC.
F i g u r e 1 : S C M 5 B 3 4 B l o ck
D ia g r a m
1 2
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For information call 800-444-7644
ISO9001:2008-Registered QMS
opper,
Specifications
Typical❇ at TA
Module
Input Range Limits
Input Resistance
Normal
Power Off
Overload
Input Protection
Continuous
Transient
Sensor Excitation Current
Pt,
Ni
u
Lead Resistance Effect
Pt,
Ni
u
CMV, Input to Output
Continuous
Transient
CMR (50 or 60Hz)
NMR
and
Ordering Information
D power
SCM5B34
to
to
to
Model
Pt
Ni
u
SCM5B34-02
to
F to
F
240Vrms max
ANSI/IEEE C37.90.1
SCM5B34-03
to
F to
F
0.25mA
1.0mA
SCM5B34-04
to
F to
F
SCM5B34-05
to
F to
F
(1)
.
(1)
1500Vrms max
ANSI/IEEE C37.90.1
160dB
95dB at 60Hz, 90dB at 50Hz
See Ordering Information
± 0.025% Span
Output Range
Output Resistance
Output Protection
Output Selection Time
(to ± 1mV of VOUT)
Output Current Limit
See Ordering Information
Continuous Short to Ground
s at load = 0 to 2000pF
Output nable ontrol
Max Logic “0”
Min Logic “1”
Max Logic “1”
Input Current “0,1”
+0.8V
+2.4V
+36V
. A
Power Supply Voltage
Power Supply Current
Power Supply Sensitivity
Pt,
Ni
u
Mechanical Dimensions
(h)(w)(d)
Environmental
Operating Temperature Range
Storage Temperature Range
Relative Humidity
Emissions EN61000-6-4
Radiated, Conducted
Immunity EN61000-6-2
RF
ESD, EFT
Pt
SCM5B34-01
Output Range†
F
Accuracy
Conformity Error(3)
Stability
Input Offset
Output Offset
Gain
Noise
Input, 0.1 to 10Hz
Output, 100kHz
Bandwidth, – 3dB
Response Time, 90% Span
Open Input Response
Open Input Detection Time
Input Range
to
F to
.
Cu
SCM5B34C-01
to
at
F to
SCM5B34C-02
.
to
at
F to
ppm of Reading
.
S C M 5 B
rms
rms
4Hz
0.2s
+8mA
Downscale
3s
+5VDC ± 5%
30mA
.
.
2.28” x 2.26” x 0.60”
(58mm x 57mm x 15mm)
to
to
0 to 95% Noncondensing
ISM, Group 1
Class A
ISM, Group 1
Performance A ± 0.5% Span Error
Performance B
SCM5B34C-03
i
SCM5B34N-01
**
Accuracy(2)
3, 4
.
3, 4
.
3, 4
.
3, 4
.
3, 4
.
3, 4
.
3, 4
.
3, 4
.
3, 4
.
F
F
to
at
F to
F
to
F to
F
RTD Standards
Type
A
Pt
Ni
u
a Coe ficient
0.00385
0.00672
0.004274
DIN
JIS
IEC
DIN 43760
JIS C 1604-1989
IEC 751
Output Ranges Available
†
Output Range Part o u fi
3. 0V to +5V
4. 0V to +10V
NONE
D
am e
SCM5B34-01
SCM5B34-01D
NOTES :
❇
ontact factory or your local Dataforth sales office for maximum values.
refers to the resistance in one lead.
Includes conformity, hysteresis and repeatability.
(3) Conformity error is ± 0.05% Span for SCM5B34N-01.
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©1995-2017 Dataforth Corporation, All Rights Reserved
1 3
ISO9001:2008-Registered QMS
S C M 5 B
Isolated Analog Signal Conditioning Products