PID Tank Window

This is the control window for a Heat OR Cool PID tank (RPU). A Heat AND/OR Cool version is also available.

The RPU's (Remote Processing Unit) controller provides proportional control, proportional with limit, and dead band (on-off) modes. Proportioning is done with ordinary on-off solenoid valves, by changing the dwell (on time) for each cycle. This works because the tank has a long thermal time constant. The controller supports our de-ice method for fast, accurate cold stabillizations.

The Valve Sensor is typically used to supervise the solenoid valve. 'Glycol' alarms are the result of the valve not getting cold when glycol should flow. 'Valve' alarms are the result of the valve not getting warmer when glycol should not flow.

The Valve and Glycol alarm can be disabled, so that the sensor may be used for another purpose, such as monitoring cap temperature.


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