Carrier 33ZCVAVTRM Specifications download pdf (Page 236)

 Inverse Loop Polarity

If the output responds in reverse of what is expected, reverse

the polarity of the submaster gain (+/-). An example of this

condition is when the reference requires heat, but the valve

goes closed or moves towards closed. After the required

corrections are made, re-evaluate for the other possible

conditions.

3. Set the Master Integral Gain to 0.

4. Adjust the Master Proportional Gain.

At this point, the submaster loop is stable and its gain has

been adjusted for proper response. Adjust the setpoint to a

value +/- 5% away from current conditions at the controlling

sensor (normally the space sensor) and remove the submaster

force to allow the master loop to calculate a new submaster

reference (based on the amount of error between the master

sensor and the setpoint). This will allow the equipment to

operate with a legitimate load. Observe the loop response and

determine if the following condition is present:

 Loop Oscillation.

If the submaster reference swings wildly from its maxi-

mum to its minimum allowable value, the most likely

cause is an excessive amount of master proportional gain.

Reduce the master proportional gain in increments of

50% until stability results, then increase its value by half

of the reduced amount. Since the master loop in this

example runs every two minutes, you are advised to allow

a minimum of eight minutes (four loop iterations) be-

tween successive gain adjustments. The intent is to

produce a steady output signal without reaching the

minimum and maximum submaster values. At this point

the loop should stabilize at an output that will likely not

achieve setpoint. This is normal, and we will compensate

for this by adjustment of the integral gain.

5. Set the Integral Gain.

Once the proportional gain is established, input a value of

integral gain that is between 10% and 50% of the proportional

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Carrier 33ZCVAVTRM Specifications Page 236