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Old 07-19-2020, 10:47 PM
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Franklin Sankar Franklin Sankar is offline
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Thanks Brian. I was using the following which I found in the watlow 93 site
I will try yours tomorrow.

1. Apply power to the Series 93 and enter a set point. Set Operation parame- ters as follows: [``Pb] to [```1], [``rE] / [``It] to [`)00], [``rA] / [``dE] to [`)00], [``Ct] to [``%0], [`CAL] to [```0], [`AUt] to [```0].
2. Proportional Band Adjustment: Gradually increase [``Pb] until the upper display temperature stabilizes to a constant value. The process tem- perature will not be right on set point because the initial reset value is 0.00 repeats per minute. (When [``Pb] is set to 0; [``rE] / [``It] and [``rA] / [``dE] are inoperative, and the Series 93 functions as a simple on-off con- troller.) The [`HSC] parameter determines the switching differential value.
3. Reset/Integral Adjustment: Gradually increase [``rE], or decrease [``It] until the upper display temperature begins to oscillate or "hunt." Then slowly decrease [``rE] or increase [``It] until the upper display sta- bilizes again near the set point.
4. Cycle Time Adjustment: Set [``Ct] as required. Faster cycle times sometimes achieve the best system control. However, if a mechanical contac- tor or solenoid is switching power to the load, a longer cycle time may be de- sirable to minimize wear on the mechanical components. Experiment until the cycle time is consistent with the quality of control you want. [``Ct] will not appear on units with a process output.
5. Rate/Derivative Adjustment: Increase [``rA] / [``dE] to 1.00 minute. Then raise the set point by 11 to 17C, or 20 to 30F. Observe the system's approach to the set point. If the load temperature overshoots the set point, in- crease [``rA] / [``dE] to 2.00 minutes.
Raise the set point by 11 to 17C, or 20 to 30F and watch the approach to the new set point. If you increase [``rA] / [``dE] too much, the approach to the set point is very sluggish. Repeat as necessary until the system rises to the new set point without overshooting or approaching the set point too slowly.
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