Hitachi WJ Series User Manual page 231

Chapter 9
3
Setting the PID target value input source and feedback input source
 Set the PID feedback value input source with "PID feedback input source selection [A076]",
and the PID target value input source with "Frequency input source selection [A001]
 If the PID feedback input source is "[Ai2] terminal input (00)" or "[Ai1] terminal input (01)",
and the PID target value input source is "Control terminal (01)", the "AT selection [A005]" will
be disabled, and the analog input not set by [A076] becomes the target value input source.
(Example)
 If the PID feedback value input source is "Modbus communication (02)", write the feedback
value in the holding register address 0006h, with 10000 being 100%.
Register
number
0006h
(Note) This register is only writable when [A076] is set to "Modbus communication (02)".
 If the PID target value input source or PID feedback value input source is "Pulse input", the
value retrieved is converted to a percentage of the maximum frequency (100%), with the
maximum frequency being the pulse frequency set in "Pulse frequency scale [P055]". For
details on pulse frequency commands, refer to "9.2.8 Setting Pulse Input as the Frequency
Command Input Source".
 If the PID target value input source or PID feedback value input source is the "Calculation
function result," refer to "9.2.11 Setting a Calculation Operation on Two Frequency
Commands as the Frequency Command Input Source" for details.
4
Setting and adjusting proportional gain, integral gain, and derivative gain
 Set the "PID proportional gain [A072]", "PID integral gain [A073]," and "PID derivative gain
[A074]" according to the actual control target.
 If the response is not stable in PID operation, refer to the procedure below to make
adjustments.

Even when the PID target value fluctuates,
output response is slow, and the feedback value
changes slowly.

Feedback values change quickly and are not
stable.

Overshooting and hunting occur.

Feedback values gradually fluctuate.

There is a delay before operations stabilize.

The PID target value and feedback value do not
match easily.

There is a slow response even when proportional
gain is increased.

Small-scale hunting occurs.

There is a greater susceptibility to external
disturbances, and operations take longer to
stabilize.
. "2nd-motor control [SET]" target parameter. The second control parameter is also subject to setting.
1
*
If [A076] is "[Ai2] terminal input (00)" and [A001] is "Control circuit terminal
block (01)", the PID target value input source is the [Ai1] terminal input.
Code Item
- PID feedback
Event ▷
9-8-5
R/W Data range
R/W 0 to 10000
Example of countermeasures
Increase the "PID proportional gain [A072]".
Decrease the "PID proportional gain [A072]".
Increase the "PID integral time constant
[A073]".
Decrease the "PID integral time constant
[A073]".
Increase the "PID derivative gain [A074]".
Decrease the "PID derivative gain [A074]".
Inverter Functions
*1"
.
Resolution (%)
0.01 (%)