Output Deviation For Pid Control - Hitachi SJ300 Series Instruction Manual

Output Deviation
The PID loop error is defined as the
magnitude (absolute value) of the differ-
for PID Control
ence between the Setpoint (target value)
and the Process Variable (actual value).
When the error magnitude exceeds the
preset value for C044, the [OD] terminal
signal turns ON. Refer to
Operation" on page
Code
Valid for
outputs:
Required
settings:
Notes:
• The default deviation value is set to 3%. To
NOTE: The example circuit in the table above 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.
"PID Loop
4–71.
Opt.
Symbol Function Name
04 OD Output deviation
for PID control
11, 12, 13, 14, 15,
AL0 – AL2
C044
change this value, change parameter C044
(deviation level).
Error
(SP-PV)
C044
Set
value
C044
[OD]
Signal ON
Output
Description
State
ON when PID error is more than the set
threshold for the deviation signal
OFF when PID error is less than the set thresh-
old for the deviation signal
Example: (Requires output configuration—
see page 3–53):
Inverter output terminal circuit
RY
See I/O specs on page 4–9.
4–47
SJ300 Inverter
Process variable
Setpoint
ON
t
OD
14 13 11
CM2
15 12
+
–