Hitachi X200 Series instruction manual 41, Output Deviation for PID Control

4−41

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.

SP,PV

C044

C044

[OD] 1 signal 0

Process variable

Setpoint

ON ON

t

Option	Terminal	Function Name	State	Description
Code	Symbol
04	OD	Output Deviation for	ON	when PID error is more than the set threshold for
		PID Control		the deviation signal.
			OFF	when PID error is less than the set threshold for
				the deviation signal
Valid for inputs:		11, AL0 – AL2		Example for terminal [11] (default output
Required settings		C044		configuration shown – see page 3-54):
Notes:				Inverter output
• The default difference value is set to 3%. To				terminal circuit	OD
change this value, change parameter C044
(deviation level).

•The example circuit for terminal [11] drives a

relay coil. Note the use of a diode to prevent the	CM2		11
negativegoing turn-off spike generated by the
coil from damaging the inverter’s output
transistor.		RY

Example for terminal [AL0], [AL1], [AL2] (requires output configuration – see page 4-35 and 3-54):

Inverter logic			OD
circuit board
		AL0	AL1	AL2
	Power
				Load
	supply

Operations and Monitoring

See I/O specs on page 4-6