honeywell UDC2300 minipro

Hi folks, I know this is a plc forum, but this question is related. I have a honeywell UDC 2300 mini pro limit controller. Is there anyway that this can be converted to a basic on/off controller, meaning I want to take the latching off of the limit relay and control the temperature with it.

Thanks
Rusty

Answer: No, the primary relay control output is latched and cannot be used in an unlatched mode. This is a requirement from UL and FM, whose approvals are printed on the paper tag on the side of the unit.

However, if that model has an alarm output card, the alarms are traditional on-off, unlatched, unless you select 'latch' for an alarm.

One drawback is that the setpoint for the alarms is 'buried' under the alarms setup, awkward to get to if you need to change SP frequently.

However, if you set the alarm up as a 'deviation' alarm, the alarm SP would 'track' the primary setpoint ±1° or 2 or whatever, depending on the value you put in for the alarm SP.

Dan

THere's no setting for 'action' for an alarm. You'll have to pick the action you want (closed contacts to call for heat) by wiring.

I can't recall whether that model has form C contacts (NC-C-NO) or Form A (two terminals). If Form A, then there's a jumper inside to pick whether the contacts are NO or NC.

I believe the alarm are failsafe, meaning the alarm relay coil is energized in the normal, non-alarm state, but you might want to test the state when the power is off, to see.

Thanks Dan, I'll try the deviation approach, it may keep me from buying a new temp controller.