458
Output Deviation for PID Control
The PID loop error is defined as the
magnitude (absolute value) of the difference
between the Setpoint (target value) and the
Process Variable (actual value). When the
error magnitude exceeds the preset value
for , the [OD] terminal signal turns ON.
Refer to
"PID Control" on page 3-31.
Option
Terminal
Code
Symbol
OD
Valid for inputs:
Required settings
Notes:
The default difference value is set to 3%. To
change this value, change parameter
(deviation level).
The example circuit for terminal [11] drives a relay
coil. Note the use of a diode to prevent the
negative-going turn-off spike generated by the coil
from damaging the inverter's output transistor.
Function Name
State
Output Deviation for
PID Control
11, 12, AL0 – AL2
SP,PV
[OD]
1
signal
0
ON
when PID error is more than the set threshold for
the deviation signal.
OFF
when PID error is less than the set threshold for the
deviation signal
Example for terminal [11] (default output
configuration shown – see
Inverter output
terminal circuit
Example for terminal [AL0], [AL1], [AL2] (requires
output configuration – see
Inverter logic
circuit board
See I/O specs on
Process variable
Setpoint
ON
ON
Description
page
3-89):
OD
CM2
11
RY
page 4-51 and
OD
AL0
AL1
AL2
Power
Load
supply
page 4-6
t
3-91):