Hitachi CONVENTION 14 instruction manual 4 43

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 C044, the [OD] terminal signal turns ON.
Refer to “PID Loop Operation” on page 4–
56.
Option
Code
Terminal
Symbol FunctionName State Description
ON when PID error is more than the set threshold for
the deviation signal.
04 OD Output Deviation for
PID Control
OFF when PID error is less than the set threshold for
the deviation signal
Validfor inputs: 11, AL0 – AL2
Requiredsettings C044
Notes:
xThe default difference value is set to 3%. To
change this value, change parameter C044
(deviation level).
xThe 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.
Example for terminal [11] (default output
configuration shown – see page 3-54):
Example for terminal [AL0], [AL1], [AL2] (requires
output configuration – see page 4-35 and 3-54):
See I/O specs on page 4-6
RY
Inverter output
terminal circuit
CM2 11
OD
AL1
Power
supply Load
AL0 AL2
Inverter logic
circuit board
OD
t
SP,PV
Setpoint
C044
C044
0
1[OD]
signal ON ON
Process variable
443
Operations and
Monitoring
4 43
Operations and
Monitoring