Omron CJ - REFERENCE MANUAL 02-2010 Reference Manual page 704

3. Instructions
Precautions
When using TPO(685) in combination with PID(190) in a cyclic task and also using an interrupt task,
temporarily disable interrupts by executing DI(693) (DISABLE INTERRUPTS) ahead PID(190) and
TPO(685). If interrupts are not disabled and an interrupt occurs between the PID(190) and TPO(685),
the control period may be shifted.
Cyclic task
Example Programming
Combining TPO(685) with PID(190)
When CIO 0.00 is ON, TPO(685) takes the manipulated variable output from PID(190) (contained in
D0), calculates the duty ratio from that manipulated variable value (Duty ratio = MV
converts the duty ratio to a time-proportional output, and outputs the pulses to CIO 2001.
In this case, CIO 20 is allocated to a Transistor Output Unit and bit CIO 2001 is connected to a solid
state relay for heater control.
0.00
668
DI
PID
PV input
S
C
PID parameters
Reception prohibited
Manipulated
D
variable
TPO
Manipulated
S
variable
Parameters
C
Pulse output
R
EI
Reception allowed
PID
10
S
PV input
D200
C
PID parameters
D0
D
Manipulated variable
TPO
S
D0 Manipulated variable
C
D5000 Parameters
R
20.01 Pulse output
D200 Set value (SV)
D201 Proportional band (P)
:
D206
:
:
D5000
1
Interrupt task
Interrupt task
When CIO 0.00 goes from OFF to ON, PID(190)
reads the parameters, performs the PID calculation
with the PV input in CIO 10, and outputs the
manipulated variable (MV) to D0.
TPO(685) calculates the duty ratio by dividing the
MV in D0 by the MV range (0FFF Hex since the
range is set to 12 bits), converts that duty ratio to a
time-proportional output, and outputs the pulse
output to bit 01 of CIO 20.
4
Output range: 4 hex
(12 bits: 0000 to 0FFF hex)
4
MV range: 4 hex
(12 bits: 0000 to 0FFF hex)
Input type: 1 hex (MV)
CS/CJ/NSJ Series Instructions Reference Manual (W474)
MV range),