651
Data Control Instructions Section 3-17
Example Example 1: 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
÷ MV range), converts the duty ratio to a time-
proportional output, and outputs the pulses to CIO 100.05.
In this case, CIO 100 is allocated to a Transistor Output Unit and bit
CIO 100.05 is connected to a solid state relay for heater control.
Note 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.
0.00
PID
1000
D200
D0
TPO
D0
D5000
100.05
S
C
D
D200
D201
:
D206
:
:
D5000
S
C
R
4
41
PV input
PID parameters
Manipulated variable
Manipulated variable
Parameters
Pulse output
Set value (SV)
Proportional band (P)
When CIO 0.00 goes from OFF to ON, PID(190)
reads the parameters, performs the PID calculation
with the PV input in CIO 1000, 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 CIO 100.05.
Output range: 4 hex
(12 bits: 0000 to 0FFF hex)
MV range: 4 hex
(12 bits: 0000 to 0FFF hex)
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