Pid control – Hitachi L2002 User Manual

Page 104

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“A” Group: Standard Functions

Configur

ing

Dr

iv

e P

a

ra

m

e

ters

3–24

PID Control

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 4–56

for more information.

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.

“A” Function

Run

Mode

Edit

Lo Hi

Defaults

Func.

Code

Name /

SRW Display

Description

–FE(F)

(EU)

–FU

(USA)

Units

A071 PID Enable

Enables PID function,
two option codes:
00... PID Disable
01... PID Enable

✘ ✔

00

00

PID Mode OFF

A072 PID proportional gain

Proportional gain has a range
of 0.2 to 5.0

✔ ✔

1.0

1.0

PID P 0001.0

A073 PID integral time

constant

Integral time constant has a
range of 0.0 to 150 seconds

✔ ✔

1.0

1.0

sec.

PID I 0001.0s

A074 PID derivative time

constant

Derivative time constant has a
range of 0.0 to 100 seconds

✔ ✔

0.0

0.0

sec.

PID D 000.00s

A075 PV scale conversion

Process Variable (PV) scale
factor (multiplier), range of
0.01 to 99.99

✘ ✔

1.00

1.00

PID Cnv 001.00%

A076 PV source setting

Selects source of Process
Variable (PV), option codes:
00... [OI] terminal (current in)
01... [O] terminal (voltage in)
02... ModBus network
03... Calculate function output

✘ ✔

00

00

PID INP OI

A077 Reverse PID action

Two option codes:
00... PID input = SP – PV
01... PID input = –(SP – PV)

✘ ✔

00

00

PID MINUS OFF

A078 PID output limit

Sets the limit of PID output as
percent of full scale,
range is 0.0 to 100.0%

✘ ✔

0.0

0.0

%

PID Vari 0000.0%

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