Martel Electronics SP200 - Manual (Page 3)

SP 200
3½ Digit Backlit LCD Voltmeter Module
PIN FUNCTIONS
1. V+ Positive power supply to the meter and LED backlighting.
2. NC Not connected.
3. GND 0V power supply connection to the meter.
4. DP3 Connect to GND to display DP3 (199.9).
5. DP2 Connect to GND to display DP2 (19.99).
6. DP1 Connect to GND to display DP1 (1.999).
7. R I Reference voltage input for the meter's A/D converter.
8. RO Precision reference voltage output. Connect to RI for normal operation.
9. BL Connect to GND to switch on the LED backlighting.
10. COM Ground for analogue section of A/D converter.
It is actively held at 2.8V below V+ and must not be allowed to sink excessive current
(>100 A) by, for instance, connecting to a higher voltage.
11. IH Positive measuring input.
IH must be no closer than 1.5V to either the positive or negative supply.
12. IL Negative measuring input.
IL must be no closer than 1.5V to the positive supply.
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).
µ
Note:
CIRCUIT DIAGRAM
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PO Box 770, Londonderry, NH 03053 1-800-821-0023
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