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Re: Chromalox 2104 temp. contrl Help
Morning Mike
Ok you can use a CFL for testing, but a regular filament style light bulb works better. CFLs really don't like cycling like that. The standby setpoint is the temperature setpoint that the controller should default to when it is not running a program. I usually set it lower than the kiln will ever get to, so that the PID equation does not start putting heat to the kiln when I don't want it running. In other words I often will set it around 30 or 40 F.
On the intervals/segments the program will automatically advance through the segments when the programmer is put into the run mode. So if you have a segment that is thirty minutes long, the programmer will take thirty minutes to accomplish it's task (ramp or soak) and then go on to the next segment in the program. If the next segment is empty the program is finished.
Guaranteed soak is a tolerance band. Basically if you tell the controller to go to say 1500 F and you tell it to get there in say 5 minutes the controller would calculate the number of degrees to rise every minute to get there. In this case the controller would be going at just under 300 F/minute. Now the controller can do the calculation and advance the numbers that fast, but your kiln could never keep up. If you had a soak of say 5 minutes in the next segment the controller would then count the 5 minutes down and be finished long before your kiln ever came up to temperature. The guaranteed soak allows you to put in a tolerance. So if you were to put in a guaranteed soak band of 10 F the controller would still try to run the temperature up at the crazy rate of 300 F/minute, but the 5 minute soak would not start until the temperature of the kiln was at 1490 F.
The PID settings are probably the hardest part to get. Every controller is a bit different, the way the kiln is built, the size of the elements, and the placement of the thermocouple all play a part in setting them. That said there is an auto tune feature in the controller. From the manual (page 29) you can set in a set point and then tell the controller to run an auto tune cycle. You need to have the temperature of the kiln be within 50 F of the target temperature to do this. So for 1700 F you need to have the kiln temp between 1650 and 1750 with the setpoint at 1700 for the auto tune to run. I would actually run it at a lower temp first like 1000 F and then see how well the values control through out the operating range of the kiln.
Just so you know I will not be around the board this weekend, as I have a show.
Carlos
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have a great weekend..
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