Campbell Scientific PS12LA, PS512M, CH12R, CH512R Power Supplies/Regulators - Manual (Page 7)

PS12LA, PS512M, CH12R, CH512R Power Supplies and Charging Regulators
3
INT
EXT
BATT
CHG
OFF ON
CHG
CHG
+12
+12
Charging
Regulator IN
OUT 3 A
Thermal
Fuse
FIGURE 2. Simplified Charging Circuit Schematic
4. Null Modem on PS512M and CH512R
The PS512M and CH12R have two 9-pin CS I/O ports on them with a null
modem between them. The ports are used to connect two 9-pin devices that
would normally be connected to the CS I/O port on a Campbell datalogger.
The charger supplies 12 volts and 5 volts to the appropriate pins on the
connector for powering the connected devices.
This cannot be used as a null modem between two RS-232
devices. CAUTION
These
look
identical
when
unplugged