
MODULARM CORPORATION
61 MALL DRIVE, COMMACK, NY 11725 TEL 631-864-3860 ∙ FAX 631-864-3863
3 After probe has stabilized for a few minutes, use the CALIBRATION SWITCHES to change
the displayed temperature agrees with reference.
4 After calibration is complete, check and readjust setpoints.
MODEL 75C CONTROL INSTRUCTIONS
The Model 75C expands the functions of the regular Model 75 by offering temperature control
capability. The control circuitry operates as an “on-off” type thermostat, maintaining temperature
between a selected setpoint and a selected differential setting. In all instances, the setpoint is the
high limit and the differential is the low limit.
SETUP AND CONNECTION IS AS FOLLOWS:
1 Terminal strip on control board is, from left to right, N/O – COMMON – N/C. Standard
control configuration is that normally open contacts make on rise. 115 or 230 VAC may be
applied across these contacts, but DO NOT EXCEED THE CONTACT RATING OF 6 AMPS.
Use contacts to activate secondary controlling devices such as contactor coils or solenoids.
2 A Pin Jumper Matrix on the Control Board enables the user to read and adjust the Control and
Differential Setpoints in accordance with the application. (NOTE: On units which share setpoints
for the alarm and control function the pin jumper matrix and separate control setpoints are
deleted. This matrix is the two rows of gold pins located near the Control Terminal Strip and it is
utilized in the following manner:
◦ ◦ ALARM PROBE
◦ ◦ CONTROL SETPOINT (HIGH LIMIT
◦ ◦ DIFFERENTIAL (LOW LIMIT
Standard location for the provided PIN Jumper on the Jumper Matrix is the ALARM PROBE
position. (NOTE: On units which share one probe for the alarm and control function the alarm
probe position has been deleted. Therefore, place the jumper in the CONTROL PROBE position
to display monitored temperature. To read CONTROL SETPOINT (HIGH LIMIT , relocate the
jumper to the CONTROL SETPOINT Pins. (NOTE: The CONTROL SETPOINT must be
adjusted first, as the DIFFERENTIAL adjustment is dependent on and affected by the CONTROL
SETPOINT. The CONTROL SETPOINT will read on the Digital Readout and is adjusted with
the gray trimpot located next to the PIN Jumper Matrix. To read the DIFFERENTIAL (LOW
LIMIT , relocate the jumper to the DIFFERENTIAL Pins and the DIFFERENTIAL SETPOINT
will be displayed. Adjust the differential with the black trimpot next to the Setpoint Trimpot.
(NOTE: Both limits are displayed as actual high and low limit values. Example: A control set
with a high limit of 38F and a low limit of 34F will display these temperatures when the control
setpoints are read. Therefore, the differential is 4F.
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