DPM 3AS-BL 3½ Digit Backlit LCD Voltmeter Module PRODUCT DESCRIPTION The DPM 3AS-BL features a 200mV d.c. measurement range with auto-zero and auto-polarity. Decimal points are user selectable. The DPM 3AS-BL features a negative rail generator which enables the meter to measure a signal referenced to its own power supply GND. LED backlighting ensures excellent readability under low light conditions. The design of the panel meter's housing allows the module to be easily snapped into a panel. The module's low cost means it will suit high and low volume applications. The DPM 3AS-BL is intended to replace the DPM 3, DPM 3S, DPM 3-BL and DPM 3S-BL in many applications, usually requiring only minor circuit modifications. FEATURES • 11mm (0.43") Digit Height • 200mV d.c. Full Scale Reading • 3.0 to 7.5V or 6.0 to 15.0V Operation • Auto-zero and Auto-polarity • Programmable Decimal Points • LED Backlighting TYPICAL APPLICATIONS ORDERING INFORMATION • Precision Instrumentation Systems • Power Supply Monitoring • Hand held instruments • Panel-Mount Indication • Low Power Voltage Measurement Stock Number DPM 3AS-BL Standard Meter ELECTRICAL SPECIFICATIONS Specification Min. Typ. Max. Accuracy (overall error) * 0.1 Linearity ±1 Sample rate 2.5 Operating temperature range 0 50 Temperature stability 250 Meter supply voltage V+ to GND configuration 3.0 5.0 7.5 V+ to Vconfiguration 6.0 9.0 15.0** Meter supply current V+ to GND configuration 350 175 V+ to Vconfiguration Backlight supply voltage 4.75 5.0 *** Backlight supply current @ 5V d.c. 40 60 Input leakage current (Vin = 0V) 1 10 * To ensure maximum accuracy, re-calibrate periodically. ** Operation of the meter beyond the maximum supply voltage rating may cause permanent damage to the meter. *** An external series resistor is required above 5V, see Applications. Unit % (±1 count) count samples/sec °C ppm/°C V d.c. V d.c. µA µA V d.c. mA pA Unless otherwise noted, specifications apply at TA=25°C, Vsupply=5Vd.c. (fclock=48kHz) and are tested with the module configured for fully floating input mode. 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). LASCAR ELECTRONICS LTD. MODULE HOUSE WHITEPARISH WILTSHIRE SP5 2SJ UK TEL: +44 (1794) 884567 FAX: +44 (1794) 884616 E-mail: [email protected] LASCAR ELECTRONICS INC. 3750 WEST 26th STREET ERIE PA 16506 USA TEL: +1 (814) 835 0621 FAX: +1 (814) 838 8141 E-mail: [email protected] www.lascarelectronics.com LASCAR ELECTRONICS (HK) LIMITED FLAT C, 5/FL., LUCKY FTY. BLDG. 63-65 HUNG TO ROAD KWUN TONG KOWLOON HONG KONG TEL: +852 2797 3219 FAX: +852 2343 6187 E-mail: [email protected] Page 2 of 4 Page 1 of 4 DPM 3AS-BL 3½ Digit Backlit LCD Voltmeter Module DIMENSIONS All dimensions in mm (inches) 2.54 (0.1) pin pitch 6.00 (0.24) a b d 13.5 (0.53) 17.5 (0.69) 20.0 (0.79) 2.00 (0.08) c 0.50 (0.02) pin width 37.5 (1.48) 40.0 (1.57) Panel cut-out: 38.0 x 18.0 (1.50 x 0.71) a. b. c. d. Panel thickness: 1.0 - 2.5 (0.04 - 0.10) 2.00 6.00 1.60 6.00 (0.08) (0.24) (0.06) (0.24) PANEL FITTING Panel Module 1 2 FUNCTIONAL BLOCK DIAGRAM L+ V+ INLO CAL DP2 12 13 DP3 V- IN LO IN HI COM REF LO REF HI GND DP1 1 BAT A/D + _ TEST CAL L+ LREF TEST V+ BAT 11 L- COM REF HI REF LO INHI (rear view) L- XDP Vref PIN CONFIGURATION 1 V- GND BAT 8 XDP www.lascarelectronics.com Page 2 of 4 Page 2 of 4 DPM 3AS-BL 3½ Digit Backlit LCD Voltmeter Module CIRCUIT DIAGRAM V+ 8 R10 100k LREF 1 C1 47nF R9 3k INHI INLO COM C2 220nF 3 2 4 C4 100nF R3 1.5k REF HI REF LO GND 6 5 7 C6 1u5 V- L+ C7 1u5 R4 C5 47pF 180k 28 V+ INT BUF R1 29 A/Z 180k 31 IN HI 30 IN LO 32 COM 34 CREF+ 33 CREF36 REF HI 35 REF LO 38 OSC3 39 OSC2 40 OSC1 a1 b1 c1 d1 e1 f1 g1 a2 b2 c2 d2 e2 f2 g2 a3 b3 c3 d3 e3 f3 g3 ab POL BP V- TEST 37 26 IC1 5 4 3 2 8 6 7 12 11 10 9 14 13 25 23 16 24 15 18 17 22 19 20 21 a1 b1 c1 d1 e1 f1 g1 a2 b2 c2 d2 e2 f2 g2 a3 b3 c3 d3 e3 f3 g3 ab POL COM DP1 DP2 DP3 22R LED1 DP3 1.999 LOBAT V+ 13 DP2 19.99 R8 1M R7 1M R6 1M BAT R2 1M R11 DP1 199.9 LCD1 1 LED2 L- 27 11 BAT R5 100k Q1 BCX19 12 10 9 XDP TEST PIN FUNCTIONS 1. 2. 3. 4. VINLO INHI COM 5. 6. 7. 8. 9. REF LO REF HI GND V+ TEST 10. 11. XDP BAT 12. 13. LL+ Negative power supply to the meter (6.0 to 15.0V meter power supply applications only). Negative measuring input. Positive measuring input. Ground for the analogue section of the A/D converter. It is actively held at 3.05V (nom.) below V+ and must not be allowed to sink excessive current (>100µA) by, for instance, connecting to a higher voltage. Negative input for reference voltage. Positive input for reference voltage. 0V power supply to the meter (3.0 to 7.5V meter power supply applications only). Positive power supply to the meter. Connect to V+ to test the LCD. Do not connect to V+ for more than a few seconds as this may damage the LCD. TEST is held actively at 5V (nom.) below V+ and is the ground for the digital section of the meter. It can be used to power external logic up to a maximum of 1mA. V+ 8 4077 Inversion of LCD drive voltage. V+ 10 1M 1M XDP Low Battery annunciator drive pin. See application on the right. 11 BAT This pin is not fitted as standard. Negative power supply to LED backlighting. 9 Positive power supply to LED backlighting. TEST BC 237 The backlighting is internally configured for 5V operation. 470k VIf a higher voltage is used, then add a series current limiting resistor Rs. SET THRESHOLD 1 See Applications for calculations of Rs. Check Link BAT is OPEN. Note: A negative supply is generated internally and mirrors the positive supply. For example: if V+ is +5V, then the internally generated Vis -5V. When measuring with the input referenced to the same supply rail as that of the panel meter, then the limitations on the input range are (V- + 1.5V) to (V+ - 1.5V). Solder Links: LREF Normally Closed. Enables the internal voltage reference circuit. Cut this link when using an external voltage reference. BAT Normally Open. Disables the Low Battery warning annunciator. Cut this link and add a low battery detection circuit to enable the Low Battery warning annunciator via Pin 11 (BAT). DP1 Normally Open. Close this solder link to enable decimal point DP1. DP2 Normally Open. Close this solder link to enable decimal point DP2. DP3 Normally Open. Close this solder link to enable decimal point DP3. www.lascarelectronics.com Page 3 of 4 DPM 3AS-BL 3½ Digit Backlit LCD Voltmeter Module SCALING Two external 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 re-calibrated 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 + 1M Vin or Iin Rb INHI 10nF DPM 3AS-BL - INLO Input Filter *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. 5V supply operation (3.0 to 7.5V Meter Power Supply) +3.0 to +7.5V 1M + ±200mV +3.0 to +7.5V 8 V+ 3 + INHI ±200mV 10nF 2 INLO 4 COM 5 - 1M V+ 3 INHI L+ 10nF L- 2 INLO 4 COM 5 - REF LO GND 7 +3.0 to +7.5V 8 13 if V+>5V then Rs=(V+ - 5V) 0.04 1M I+ 12 Rb Measuring a single ended input voltage referenced to supply, i.e. the input voltage and the meter's power supply share the same 0V rail. Ensure solder link LREF is closed. 3 INHI 10nF 2 INLO 4 COM 5 I- REF LO GND REF LO GND 7 0V 8 V+ 7 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. Ensure solder link LREF is closed. 0V Measuring a current from a circuit which is floating with respect to the DPM's supply, i.e. the current and the meter's power supply are isolated from each other. Ensure solder link LREF is closed. 9V supply operation (6.0 to 15.0V Meter Power Supply) +3.0 to +7.5V 1M + ±200mV - 8 +6.0 to +15.0V V+ 3 + INHI ±200mV 10nF 2 INLO 4 COM 5 - REF LO V- -3.0 to -7.5V 1M V+ 3 INHI Rs=(V+ - 5V) 0.04 L+ 10nF L- 2 INLO 4 COM 5 13 1M I+ 12 Rb INHI 10nF 1 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. Ensure solder link LREF is closed. DPM 3AS-BL 3 REF LO V- 1 Specifications liable to change without prior warning 8 V+ 2 INLO 4 COM 5 I- REF LO V- 1 Measuring a single ended input voltage referenced to supply, i.e. the input voltage and the meter's power supply share the same 0V rail. Ensure solder link LREF is closed. +6.0 to +15.0V 8 Issue 4 Measuring a current from a circuit which is floating with respect to the DPM's supply, i.e. the current and the meter's power supply are isolated from each other. Ensure solder link LREF is closed. December/2002 www.lascarelectronics.com 0V M.C. Applies to DPM 3AS-BL/5 Page 4 of 4 Page 4 of 4