Lightobject.com Support Forum

I have a 110 volt TCG-6131P (Fahrenheit) model. What are the contact ratings (voltage and amperage) for the output and the alarm? The spec sheet/manual for this unit does not have any information or even a simple drawing showing the function of the 9 connectors. The only thing I got was a sticker on the side of the unit indicating what the 9 connectors go to.

I am assuming the alarm itself is an electro-mechanical relay. Not sure about the output and whether it must be connected to a solidstate relay for typical pulsed PID control.

I am actually using the unit as a simple thermostat to control a valve on a millivolt gas heater (very low voltage and current, perhaps .75 volt and .5 amp) and assume that I should use the alarm relay as the on-off switch with "0" upper limit offset. I do not want rapid-cycling PID functions. If I use the regular output, I assume setting "Proportional Cycle" would only allow a maximum of 99 seconds on.

Any advice would be appreciated. You need a little more documentation for the products.

I've noticed that company responses to information requests can be fairly spotty.

After playing with the device, it looks like the Output contacts close when the current temperature is below the Setpoint and the Alarm output contacts close when the current temperature is above (depending on Upper Limit Offset setting). There is no low voltage DC output to drive a SSR, so I'm not sure how you would be able to do any form of rapid pulse control through the electromechanical relay in this unit.

Would appreciate a confirmation of this. The webpage shows a rating of 3A@220VAC on the contacts (this information is not in the PDF manual/spec for this unit).

Company really does need better documentation for this device.

I think you have the right info.

You can cycle a mechanical relay as quickly as a PID controller's SSR control mode would, but the wear and tear on the contacts (depending on the current) is pretty high with short duty cycles. But if you use an external relay with a fairly low-current coil, driven by the internal relay, then the internal relay should last a long time. It really comes down to the amount of power being switched on and off by the internal relay.

It's been a while that I didn't touch that controller. So, I got to try it before I can post an answer here. I don't want to do 'guessing' and end up any incident.

I tried to answer all question but I'm just a small 'bean' and man power is very limited here. But thanks to so many folks (richiem, tomtom, glassguy213 and others...) who helped me out. They are great and they're knowlegeable on Temp controller. Very appreicate for their help and your patience


Marco

richiem wrote:I think you have the right info.

You can cycle a mechanical relay as quickly as a PID controller's SSR control mode would, but the wear and tear on the contacts (depending on the current) is pretty high with short duty cycles. But if you use an external relay with a fairly low-current coil, driven by the internal relay, then the internal relay should last a long time. It really comes down to the amount of power being switched on and off by the internal relay.

Typically these relays are rated for 100,000 to 1,000,000 cycles, so with any rapid or pulsed cycling, you could wear it out pretty quickly. Even 1 cycle every 10 seconds would be 3 million cycles a year.

Good point Mac. I missed the original point about the application -- if this is for 24/7 use, then an SSR is by far the best choice.