V125

V 125 3½ Digit LCD Voltmeter Module PRODUCT DESCRIPTION This low cost compact LCD voltmeter module is ideally suited for high volume applications. It features an exceptionally large display in a miniature package and includes auto-zero and user-selectable decimal points. The module is supplied with a panel mounting bezel. FEATURES • Low Cost • 12.5mm (0.5") Digit Height • 200mV d.c. Full Scale Reading • 1mA (typ) @ +9V d.c. Power Supply • Auto-zero and Auto-polarity • User Selectable Decimal Points • Supplied with Mounting Bezel REAR VIEW 8 1 TYPICAL APPLICATIONS ORDERING INFORMATION • High Volume, Low Cost Systems • Power Supply Monitoring • Panel-Mount Indication Stock Number V 125 Standard Meter ELECTRICAL SPECIFICATIONS Specification Accuracy (overall error) * Linearity Sample rate Operating temperature range Temperature stability Supply voltage Supply current Min. 0-1000 reading 0-2000 reading 0 7.0 Typ. 0.25 ±3 ±5 3 300 9 1 Max. 50 12 2 Unit % (±3 counts) counts counts samples/sec °C ppm/°C V d.c. mA * To ensure maximum accuracy, re-calibrate periodically. SAFETY To comply with the Low Voltage Directive (LVD 93/68/EEC), input voltages to the module’s pins must not exceed 60Vdc. The user must ensure that the incorporation of the panel meter into the user’s equipment conforms to the relevant sections of BS EN 61010 (Safety Requirements for Electrical Equipment for Measuring, Control and Laboratory Use). Page 2 of 4 www.martelmeters.com page 1 of 4 V 125 3½ Digit LCD Voltmeter Module DIMENSIONS All dimensions in mm (inches) 50.0 (1.97) 40.7 (1.60) 24.4 (0.96) 1.6 (0.06) 1.27 (0.05) 31.0 (1.22) dia 2.5 (0.1) Pin Pitch 2.5 (0.1) Pin positions are symmetrical about the vertical centre line 45.0 (1.77) 41.5 (1.63) (1.97 ) 21.4 (0.84) 50.0 5.3 (0.20) 14.0 (0.55) 20.4 (0.80) Panel thickness: 1.0 - 3.0 (0.04 - 0.12) 2.5(0.1) dia PANEL FITTING Panel Fixing Clip Meter Fastener Bezel 1 2 FUNCTIONAL BLOCK DIAGRAM 4 3 PIN CONFIGURATION (rear view) V+ Vref COM CAL 1 INHI INLO V- 8 XDP A/D + _ L1 V+ VINHI INLO XDP DP1 DP2 DP3 REAR VIEW CAL DP3 2 1 Page 2 of 4 www.martelmeters.com page 2 of 4 V 125 3½ Digit LCD Voltmeter Module CIRCUIT DIAGRAM V+ INHI INLO 1 R2 1M 3 4 R1 300k C1 68nF 27 28 29 C2 220nF 31 C3 100nF L1 30 32 C4 100nF 34 33 35 V+ 36 R6 100k R3 100k 40 39 38 R5 3k C5 100pF INT BUF A/Z IN HI IN LO COM CREF+ CREFREF LO REF HI OSC1 OSC2 OSC3 1 V+ a1 b1 c1 d1 e1 f1 g1 a2 b2 c2 d2 e2 f2 g2 a3 b3 c3 d3 e3 f3 g3 bc4 POL V- TEST BP IC1 26 5 4 3 2 8 6 7 12 11 10 9 14 13 25 23 16 24 15 18 17 22 19 20 21 24 23 21 20 19 25 22 28 27 17 16 14 1 26 3 2 12 11 10 4 5 8 7 15 a1 b1 c1 d1 e1 f1 g1 a2 b2 c2 d2 e2 f2 g2 a3 b3 c3 d3 e3 f3 g3 ab4 POL COM DP1 199.9 18 6 DP2 19.99 13 7 DP3 1.999 9 8 LCD1 LOBAT R9 1M R8 1M DP1 DP2 DP3 R7 1M 6 37 V+ R4 1.5k V- R10 100k R11 100k Q1 3904 2 5 XDP PIN FUNCTIONS 1. 2. 3. 4. 5. 6. 7. 8. V+ VINHI INLO XDP DP1 DP2 DP3 Positive power supply connection. Negative power supply connection. Positive measuring input with reference to IN LO. Analogue inputs must be no closer than 1V to either the positive or negative supply. Negative measuring input with reference to IN HI. Connect to DP1, 2 or 3 to display required decimal point. Connect to XDP to display Decimal Point 1 (199.9). Connect to XDP to display Decimal Point 2 (19.99). Connect to XDP to display Decimal Point 3 (1.999). Solder Links: L1 Normally Closed, connects COM to INLO. www.martelmeters.com page 3 of 4 V 125 3½ Digit LCD Voltmeter Module SCALING Two resistors Ra and Rb may be used to alter the full scale reading (FSR) of the meter - see table. The meter will have to be recalibrated by adjusting the calibration potentiometer on the rear of the module. Voltage Vin Current Iin FSR 2V 20V 200V 2000V* 200µA 2mA 20mA 200mA Ra 910k 1M 1M 1M 0R 0R 0R 0R Rb 100k 10k 1k 100R 1k 100R 10R 1R Ra + INHI Vin or Iin Rb - INLO *Ensure that Ra is rated for high voltage use. APPLICATIONS Do not connect more than one meter to the same power supply if the meters cannot use the same signal ground. Taking any input beyond the power supply rails will damage the meter. Normally SHORTED Cut to OPEN Normally OPEN Solder to SHORT +7.0 to +12V +7.0 to +12V 1 1 V+ + 3 IN - 4 ±200mV HI IN LO V+ L1 DP1 XDP V 125 6 5 I+ 3 IN I- 4 HI IN LO V- L1 DP1 XDP V 125 6 5 V- 2 2 0V 0V Measuring an input voltage referenced to a floating supply, i.e. the input voltage and the meter's power supply are isolated from each other. Check Link L1 is closed. Measuring a current referenced to a floating supply, i.e. the current being measured and the meter's power supply are isolated from each other. Check Link L1 is closed. +3.5 to +6.0V 1 V+ + 3 - 4 ±200mV L1 IN HI IN LO V 125 DP1 XDP 6 5 V- 2 -3.5 to -6.0V Measuring a single ended input referenced to supply, i.e. the input voltage and the meter's power supply share the same 0V rail. Check Link L1 is open. Specifications liable to change without prior warning V 125 Issue 3 January/2002 www.lascarelectronics.com www.martelmeters.com M.C. Applies to V 125/2 Page 4 of 4 page 4 of 4