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2 Instructions
2-274
CP1E CPU Unit Instructions Reference Manual(W483)
Precautions
When using TPO(685) in combination with PIDAT(191) in a cyclic task and also using an interrupt
task, temporarily disable interrupts by executing DI(693) (DISABLE INTERRUPTS) ahead PIDAT(191)
and TPO(685). If interrupts are not disabled and an interrupt occurs between the PIDAT(191) and
TPO(685), the control period may be shifted.
Sample program
Combining TPO(685) with PIDAT(191)
When CIO 0.00 is ON, TPO(685) takes the manipulated variable output from PIDAT(191) (contained in
D0), calculates the duty ratio from that manipulated variable value (Duty ratio = MV ÷ MV range), con-
verts the duty ratio to a time-proportional output, and outputs the pulses to bit 01 of CIO 100.
In this case, CIO 100 is allocated to a Transistor Output Unit and bit CIO 100.01 is connected to a solid
state relay for heater control.
DI
EI
S
C
D
S
C
R
Reception prohibited
Reception allowed
Interrupt task
Interrupt task
Cyclic task
PIDAT
PV input
PID parameters
Parameters
TPO
Pulse output
Manipulated
variable
Manipulated
variable
0.00
PIDAT
10
D200
D0
TPO
D0
D500
100.01
S
C
D
D200
D201
:
D206
:
:
D500
S
C
R
4
41
PV input
PID parameters
Manipulated variable
Manipulated variable
Parameters
Pulse output
Set value (SV)
Proportional band (P)
Output range: 4 hex
(12 bits: 0000 to 0FFF hex)
MV range: 4 hex
(12 bits: 0000 to 0FFF hex)
Input type: 1 hex (MV)
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 100.