Hitachi L100 Output Deviation for PID Control

4–26

Using Intelligent Output Terminals

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 C_44, the [OD] terminal signal turns ON. Refer to “PID Loop Operation” on page 4–32.

SP, PV				Process variable
					Setpoint
	C 44
	C 44
[OD]		1
			ON			ON
Signal		0

t

Operations and Monitoring

Option

Terminal

Function Name

Output

Description

Code

Symbol

State

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 outputs:

11, 12

Example (requires output configuration—

see page 3–36):

Required settings:

C_44

Notes:

Inverter output

OD

• The default difference value is set to 3%. To change

terminal circuit

this value, change parameter C_44 (deviation

level).

H

O

OI

L

FM

CM2

12

11

+

–

RY

See I/O specs on page 4–6.

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.