Martel Electronics SP300 - Manual (Page 3)

PIN FUNCTIONS
1. V+ Positive power supply to the meter.
2. 0V 0V power supply connection to the meter.
3. COM Ground for analogue section of 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.
4. IH Positive measuring input.
5. IL Negative measuring input.
6. DP1 Connect to 0V to display DP1 (199.9).
7. DP2 Connect to 0V to display DP2 (19.99).
8. DP3 Connect to 0V to display DP3 (1.999).
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).
LCOM Normally Open. Connects IL to COM.
µ
Note:
Solder Links:
CIRCUIT DIAGRAM
Page 3 of 4
SP 300
3½ Digit LED Voltmeter Module
www.lascarelectronics.com
1
4
5
3
2
6
9
16
7
8
PO Box 770, Londonderry, NH 03053 1-800-821-0023
www.martelcorp.com