Instruction Manual

Instruction Manual

D103434X012

Blocks

November 2014

PID Equation Structures for Enhanced PID Block

Note

Extended parameters are not available at this time for all host systems. Refer to your host system documentation, or contact your

Emerson Process Management sales office for additional information.

Configure the STRUCTURECONFIG [71] parameter to select the PID equation structure. You can select one of the

following choices:

D Proportional, integral, and derivative on error (PID)

D Proportional and integral on error, derivative on PV (PI_D)

D Integral on error, proportional and derivative on PV (I_PD)

D Proportional on error, derivative on error (PD)

D Integral on error, derivative on error (ID)

D Integral on error, derivative on PV (I_D)

D Two degrees of Freedom (2DOF)

Reverse and Direct Action

To configure the block output action, set the Direct Acting control option. This option defines the relationship

between a change in PV [7] and the corresponding change in output. With Direct Acting enabled (True), an increase in

PV results in an increase in the output.

You can set control options in Manual or Out of Service mode only.

Alarm Detection

A block alarm will be generated whenever the BLOCK_ERR [6] has an error bit set. The types of block error for the PID

block are defined above.

Process alarm detection is based on the PV [7] value. You can configure the alarm limits of the following standard

alarms:

D High (HI_LIM [51])

D High high (HI_HI_LIM [49])

D Low (LO_LIM [53])

D Low low (LO_LO_LIM [55])

Additional process alarm detection is based on the difference between SP [8] and PV [7] values and can be configured

via the following parameters:

D Deviation high (DV_HI_LIM [57])

D Deviation low (DV_LO_LIM [59])