3–22

“A” Group: Standard Functions

PID Control

Configuring

Drive Parameters

 

 

When enabled, the built-in PID loop calculates an ideal inverter output value to cause a loop feedback process variable (PV) to move closer in value to the setpoint (SP). The frequency command serves as the SP. The PID loop algorithm will read the analog input for the process variable (you specify the current or voltage input) and calculate the output.

•A scale factor in A075 lets you multiply the PV by a factor, converting it into engineering units for the process.

•Proportional, integral, and derivative gains are all adjustable.

•See “PID Loop Operation” on page 4–54 for more information.

 

 

“A” Function

Run

 

Defaults

 

 

 

 

 

 

 

 

 

 

Func.

Name /

 

Description

Mode

–FEF

–FU

 

Units

 

Edit

 

Code

SRW Display

 

(EU)

(USA)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A071

PID Enable

 

Enables PID function,

✘

00

00

 

—

 

 

 

two option codes:

 

 

 

 

 

 

PID Mode

OFF

 

 

 

 

 

 

00

... PID Disable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

01

... PID Enable

 

 

 

 

 

 

 

 

 

 

 

 

 

A072

PID proportional gain

Proportional gain has a range

✔

1.0

1.0

 

—

 

 

 

of

0.2 to 5.0

 

 

 

 

 

 

PID P

0001.0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A073

PID integral time

Integral time constant has a

✔

1.0

1.0

 

sec.

 

constant

 

range of 0.0 to 150 seconds

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PID I

0001.0s

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A074

PID derivative time

Derivative time constant has a

✔

0.0

0.0

 

sec.

 

constant

 

range of 0.0 to 100 seconds

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PID D

000.00s

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A075

PV scale conversion

Process Variable (PV) scale

✘

1.00

1.00

 

—

 

 

 

factor (multiplier), range of

 

 

 

 

 

 

PID Cnv

001.00%

 

 

 

 

 

 

0.01 to 99.99

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A076

PV source setting

Selects source of Process

✘

00

00

 

—

 

 

 

Variable (PV), option codes:

 

 

 

 

 

 

PID INP

OI

 

 

 

 

 

 

00

... [OI] terminal (current in)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

01

... [O] terminal (voltage in)

 

 

 

 

 

 

 

 

02

... ModBus network

 

 

 

 

 

 

 

 

03

... Calculate function output

 

 

 

 

 

 

 

 

 

 

 

 

 

A077

Reverse PID action

Two option codes:

✘

00

00

 

—

 

 

 

00

... PID input = SP – PV

 

 

 

 

 

 

PID MINUS

OFF

 

 

 

 

 

 

01

... PID input = –(SP – PV)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A078

PID output limit

Sets the limit of PID output as

✘

0.0

0.0

 

%

 

 

 

percent of full scale,

 

 

 

 

 

 

PID Vari 0000.0%

 

 

 

 

 

 

range is 0.0 to 100.0%

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTE: The setting A073 for the integrator is the integrator’s time constant Ti, not the gain. The integrator gain Ki = 1/Ti. When you set A073 = 0, the integrator is disabled.