Setting up a PID and gas controller?
I am trying to automate my temperature control and am using the following:
TET-612 Temperature Controller
Honeywell VR8200 A 2132 Gas Control
I was wondering if anyone had advice on wiring between the PID and the gas valve. I do not want to fry anything.
The PID has two types of outputs:
SSR activated voltage: open circuit: 8V; short circuit: 40mA.
Relay Contact volume: AC220V / 3A.
Gas Valve is controlled by 24VAC at 0.5A
Automate temperature control of what?
Shouldn't really matter what since it's the same operation but I am heating liquids.
If you're heating liquids in an open tank, then you don't need PID control--and I argue that you don't want it either. These algorithms are difficult to tune without experience, and give you no added benefit. Besides, your gas valve is not set up for PID. Using on/off relay control is much simpler and will heat your liquid until the temperature controller senses a high limit, at which time it will open the heating circuit. Simply switch the 24v through the J1 alarm relay contacts in the temperature controller. Make sure to program the controller parameters correctly: Select your tank thermocouple/thermistor type from Table 2; set outy=0; set Rd=0. As long as you use J1 relay "output", you are merely switching the 24v permissive from the gas valve, and should not "fry" anything. BTW, this temperature controller doesn't look like it is really set up for on/off control--I don't see how to change the deadband of the alarm relay.
What controller do you recommend then for the gas controller? I only need 60-130k BTUs and I want to keep my temperature stable without having to watch the temperature gauge.
If you have an alternative economical setup then by all means educate me.
You can use the controller you have now, or if you want to invest in another one, check out FUJI controllers from Premier Stainless. They have all the bells & whistles at an economical price. You will want to set your deadband to around 2 degrees F to keep the burner from cycling on and off repeatedly. You should have no problem maintaining your temperature.