Perma Pure Baldwin-Series M225 - Manual (Page 13)

Section H: Test & Adjustment Procedures 13
B. Display Board (not standard on the Model M225)
(1) WARNING: Before connecting power to the cooler, be aware of the
HAZARDOUS LIVE VOLTAGE on the control board. Disconnect power from the
cooler before opening the swing-down "L-door". Remove display cover from the
front of the swing-down "L-door". Connect a voltmeter between the ground test
point, TP7 on the main control board and TP1 on the display board, the red lead to
TP1 and the black lead to TP7.
(2) Connect power to the cooler and allow the temperature of the cooler to stabilize
around 5
° C.
(3) Adjust POT1 on the display board so the display corresponds to the voltmeter
reading. That is, if the voltmeter reads 0.5vdc, adjust the pot so that the display
reads 0.5.
C. Auxiliary Analog Output Board (not standard on the model M225)
(1) WARNING: Before connecting power to the cooler, be aware of the
HAZARDOUS LIVE VOLTAGE on the control board. Disconnect power from the
cooler before opening the swing-down "L-door". Remove the thermocouples from
TB5 and TB6 on the auxiliary analog output board. The thermocouple generator
should not be connected to either of the thermocouple inputs at this time. Connect
power to the cooler. After 10 to 20 seconds, the red LED(s) (thermocouple failure
indicator) on the auxiliary analog output board should be on.
(2) Connect the thermocouple generator to the Channel 1 thermocouple input (TB5
terminal), inserting the yellow wire into the terminal marked Y and the red wire into
the terminal marked R. Turn on the generator. The red LED (CR5) should turn off.
Set the thermocouple generator to 0
° C.
For Voltage Output
(3) If the auxiliary analog output board is set for voltage output, set the voltmeter to
20vdc range. Connect the voltmeter to TB2 (the channel 1 voltage output terminal),
the black lead to the negative (-) terminal and the red lead to the positive (+)
terminal.
(4) Adjust POT4 (the zero pot) to obtain a 0vdc reading on the voltmeter.
(5) Set the thermocouple generator to 25
° C.
(6) Adjust POT1 (the span pot) to obtain a full scale voltage reading on the
voltmeter. This value will depend on the gain that was specified for the cooler at the
time of manufacture. Available gains are 0-1.0vdc, 0-2.5vdc, 0-10.0vdc for a 0
° C-
25 ° C temperature range.