Instruction Manual

748467-A January 2002

Model MicroCEM

PID Setting

Description

 

Proportional Gain. This parameter is set by using typical PID

PSetting

tuning methods. The P setting is mandatory and is the first pa-

rameter to adjust. It provides a command directly proportional to

 

 

the error.

 

 

 

Integral Gain. This parameter is set by using typical PID tuning

ISetting

methods. The I setting is optional and is used to make small ad-

justments to correct a small error which persists for a period of

 

 

time.

 

Derivative Gain. This parameter is set by using typical PID tuning

 

methods. The D setting is optional. It is used to adjust the com-

DSetting

mand based on change in error. It can be used to reduce over-

 

shoot, which typically occurs when the P settings is used by itself.

 

This parameter tends to amplify any noise present in the input.

 

Should be set to the typical warm-up/cool-down speed in

 

°C/second when the heater/cooler is operated at 100% power.

MaxSpeedSetting

Increasing this value effectively decreases the Proportional, Inte-

 

gral and Derivative gain. Decreasing this value effectively in-

 

creases the Proportional, Integral and Derivative gain.

 

Integral Reset Error. Setting used to reset Integral value when

ResetIntegralError

error is larger than this value. This parameter is used to prevent

the integral value from building up while the error is large and

 

 

then causing overshoot when the setpoint is reached.

IntegralMaxPercent

Maximum percent output power that can be accumulated by the

Integral component. (0-100) The default is 10 percent.

 

IntegralMinPercent

Minimum percent output power that can be accumulated by the

Integral component. (0-100) The default is 10 percent.

 

MaxPercent

Maximum zone output power in percent (0-100).

MinPercent

Minimum zone output power in percent (0-100).

MinAlternationPercent

Minimum

SetPoint

This is the temperature setpoint, in degrees Celsius, for this tem-

perature control loop.

 

LowTempLimit

If the temperature (°C) is below this value during the MicroCEM

process (not including the warm-up phase) an alarm will occur.

 

HighTempLimit

If the temperature (°C) is above this value during the MicroCEM

process (not including the warm-up phase) an alarm will occur.

 

 

If the current reading is below the maximum-off current while the

MaxOffCurrent

heater is turned off, the heater has failed with a Heater Control

 

failure.

 

If the current reading is below the minimum-on current while the

MinOnCurrent

heater is turned on, the heater has failed with a Heater Burnout

 

status.

Table 3-6. PID Settings – Sections Descriptions

3-16

Operation

Rosemount Analytical Inc. A Division of Emerson Process Management