product description the dpm 3as-bl features a 200mv d.c. measurement range with auto-zero and auto-polarity. decimal points are user selectable. led backlighting ensures excellent readability under low light conditions. easily snapped into a panel. the module's the dpm 3as-bl features a negative rail generator which enables the meter to measure a signal referenced to its own power supply gnd. the design of the panel meter's housing allows the module to be 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 ?11 ? 200mv d.c. full scale reading ? 3.0 to 7.5v or 6.0 to 15.0v operation ? ? ? mm (0.43") digit height programmable decimal points led backlighting auto-zero and auto-polarity typical applications ? precision instrumentation systems ? power supply monitoring ? hand held instruments ? panel-mount indication ? low power voltage measurement ordering information stock number standard meter dpm 3as-bl dpm 3as-bl 3? digit backlit lcd voltmeter module 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). page2of4 page 2 of 4 page1of4 www.lascarelectronics.com lascar electronics ltd. module house whiteparish wiltshire sp5 2sj uk tel: +44 (1794) 884567 fax: +44 (1794) 884616 e-mail: sales@lascar.co.uk 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: b4lascar@samsongroup.com.hk electrical specifications specification min. typ. max. unit accuracy (overall error) * 0.1 % (1 count) linearity 1 count sample rate 2.5 samples/sec operating temperature range 0 50 c temperature stability 250 ppm/c meter supply voltage v+ to gnd configuration 3.0 5.0 7.5 v d.c. 175 a backlight supply voltage 4.75 5.0 *** v d.c. backlight supply current @ 5v d.c. 40 60 ma input leakage current (vin = 0v) 1 10 pa * 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. v+ to v- configuration 6.0 9.0 15.0** v d.c. meter supply current v+ to gnd configuration 350 a v+ to v- configuration m m unless otherwise noted, specifications apply at t =25c, v =5vd.c. (f =48khz) and are tested with the module configured for fully floating input mode. a supply clock lascar electronics inc. 3750 west 26th street erie pa 16506 usa tel: +1 (814) 835 0621 fax: +1 (814) 838 8141 e-mail: us-sales@lascarelectronics.com
40.0 (1.57) 37.5 (1.48) 17.5 (0.69) 20.0 (0.79) a. 2.00 (0.08) b. 6.00 (0.24) c. 1.60 (0.06) d. 6.00 (0.24) 0.50 (0.02) pin width 6.00 (0.24) 13.5 (0.53) 2.00 (0.08) 2.54 (0.1) pin pitch ab d c panel thickness: 1.0 - 2.5 (0.04 - 0.10) panel cut-out: 38.0 x 18.0 (1.50 x 0.71) dimensions all dimensions in mm (inches) dpm 3as-bl 3? digit backlit lcd voltmeter module panel fitting pin configuration (rear view) functional block diagram vref module 1 panel 2 page2of4 page 2 of 4 page2of4 1 8 a/d + _ inhi ref hi com inlo ref lo bat xdp gnd v+ v- test l- l+ cal www.lascarelectronics.com cal lref dp1 dp2 dp3 bat 11 12 13 1 bat xdp l- test l+ v+ gnd ref hi ref lo com in hi in lo v-
dpm 3as-bl 3? digit backlit lcd voltmeter module page3of4 circuit diagram www.lascarelectronics.com pin functions 1. v- negative power supply to the meter (6.0 to 15.0v meter power supply applications only). 2. inlo negative measuring input. 3. inhi positive measuring input. 4. com 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 (>100 a) by, for instance, connecting to a higher voltage. 5. ref lo negative input for reference voltage. 6. ref hi positive input for reference voltage. 7. gnd 0v power supply to the meter (3.0 to 7.5v meter power supply applications only). 8. v+ positive power supply to the meter. 9. test 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. 10. xdp inversion of lcd drive voltage. 11. bat low battery annunciator drive pin. see application on the right. this pin is not fitted as standard. 12. l- negative power supply to led backlighting. 13. l+ positive power supply to led backlighting. the backlighting is internally configured for 5v operation. if a higher voltage is used, then add a series current limiting resistor rs. see applications for calculations of rs. a negative supply is generated internally and mirrors the positive supply. for example: if v+ is +5v, then the internally generated v- is -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). 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. m note: solder links: v+ 8 3 2 4 6 5 7 1 13 12 inhi inlo com ref hi ref lo gnd v- l+ l- int v+ v- test a1 a1 27 1 26 28 29 31 30 32 34 36 35 33 d1 d1 e1 e1 f1 f1 dp1 199.9 dp2 19.99 dp3 1.999 g1 g1 f2 f2 a2 a2 g2 g2 e3 e3 b2 b2 a3 a3 f3 f3 c2 c2 b3 b3 g3 g3 d2 d2 c3 c3 ab ab e2 e2 d3 d3 b1 b1 c1 c1 5 2 8 6 7 13 12 25 18 11 23 17 10 16 22 9 24 19 14 15 4 3 buf a/z in hi in lo com cref+ cref- ref hi ref lo ic1 lcd1 r4 r11 led1 led2 180k 22r 47pf 1u5 1u5 c5 c7 c6 c4 100nf c1 47nf r1 180k c2 220nf lref dp1 dp2 dp3 bat r10 100k r9 3k r3 1.5k 37 pol pol bp com 20 21 40 39 38 osc3 osc2 osc1 10 11 9 v+ xdp bat test lobat r8 1m r5 100k r2 1m q1 bcx19 r7 1m r6 1m check link bat is open. v+ v+ xdp bat test 8 10 1 v- 1m 470k 1m 4077 11 9 set threshold bc 237
dpm 3as-bl 3? digit backlit lcd voltmeter module specifications liable to change without prior warning dpm 3as-bl issue 4 december/2002 m.c. applies to dpm 3as-bl/5 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. page4of4 page 4 of 4 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. fsr ra rb 2v 910k 100k 20v 1m 10k (vin) 200v 1m 1k 2000v* 1m 100r 200 a 0r 1k 2ma 0r 100r ( in) 20ma 0r 10r 200ma 0r 1r m i voltage current page4of4 *ensure that ra is rated for high voltage use. 5v supply operation (3.0 to 7.5v meter power supply) 9v supply operation (6.0 to 15.0v meter power supply) 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. 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. 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. 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. 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. 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. www.lascarelectronics.com +3.0 to +7.5v 7 8 12 13 3 2 4 5 v+ inhi inlo com ref lo gnd + - 200mv 0v l- l+ if v+>5v then rs=(v+ - 5v) 0.04 1m 10nf +6.0 to +15.0v 1 8 12 13 3 2 4 5 v+ inhi inlo com ref lo v- + - 200mv 0v l- l+ rs=(v+ - 5v) 0.04 1m 10nf +3.0 to +7.5v +6.0 to +15.0v 7 1 8 8 3 3 2 2 v+ v+ inhi inhi 4 4 5 5 com com ref lo ref lo inlo inlo 0v 0v gnd v- rb rb i + i + i- i- 1m 1m 10nf 10nf +3.0 to +7.5v 7 8 3 2 4 5 v+ inhi inlo com ref lo gnd + - 200mv 0v 1m 10nf +3.0 to +7.5v -3.0 to -7.5v 1 8 3 2 4 5 v+ inhi inlo com ref lo v- + - 200mv 1m 10nf + - ra 1m rb inhi vin or in i inlo dpm 3as-bl 10nf input filter
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