Sheet 1

The overall function of the temperature controllers is to keep the camera lenses from frosting over in cool, damp weather. This is accomplished by strip heaters, thermocouples and the Omega temperature controllers. Briefly, the temperature controller senses the temperature of each camera and turns on and off it output which we wired to the solid-state relays that supply 115VAC to the strip heaters. When the temperature is sensed to be higher then the desired point the output turns off removing the voltage to the heater.

At this writing, it is not known if the controller is working in proportional or on/off mode. This is determined by the settings of the temperature controllers internal jumpers. See page 6 of the manual. Here

This drawing shows the wiring for the camera temperature controllers. The heaters are silicon rubber strip heaters. Each one wraps almost entirely around its camera. A thermocouple is attached to each camera to provide feedback to the controllers. In addition, there is a K-type thermocouple attached to the blue camera that can be plugged into a temperature meter. Note, many newer digital VOMs can also read out the temperature of a K-type thermocouple.

On the left side of the drawing, there are two input connectors. The top is a 10-pin MS-style connector that provides an input for a 12VDC supply. The 12V is used to power the control side of the Crydom solid-state relays. Beneath the MS connector is the AC entry module. Both the 12VDC and the 115VAC are wired directly to the main terminal strip. At the top of the drawing are the connections to the thermocouples and the strip heaters. The heaters are connected through 6-pin MS-style connectors and the thermocouples are connected to screw terminals on the temperature controllers. A removable plate provides access to the thermocouple connections. The heaters are connected to the main terminal strip.

The terminal strip interconnects wires to the solid-state relays and the Omega temperature controllers, (See manual here), and the strip heaters. The only wires not connected to the terminal strip are the wires leading to the thermocouples which connect directly to the red and blue controllers. The +12V line is connected to TB-1 and its GND to TB-2. The +12V is wired to the common contact of each of the temperature controllers relays via terminal 7. The GND is connected to terminal 4 of the two solid-state relays. The other side of each solid-states control section is wired to the normally open contact of the temperature controllers. The AC High side is wired to TB-3 and from there to terminal 5 of the temperature controllers and terminal 1 of the solid-state relays. The AC Neutral side is wired to TB-4, TB-6, and TB-7 and from there to terminal 1 of the temperature controllers and to pin D of the heater connectors. The output terminal of the solid-state relays are wired to pin A of the heater connectors