IDEC MicroSmart - Manual (Page 372)

21: PID I NSTRUCTION
21-16 « FC4A M ICRO S MART U SER ’ S M ANUAL »
Ladder Program
The ladder diagram shown below describes an example of using the PID instruction. The user program must be modified
according to the application and simulation must be performed before actual operation.
Set Analog Module Parameters (ANST) Dialog Box
WindLDR has a macro to program parameters for analog I/O modules. Place the cursor where to insert the ANST instruc-
tion, click the right mouse button, and select Macro Instructions > ANST (Set Analog Module Parameters) . In the
ANST dialog box, press the Configure button under Slot 1, and program as shown below.
M8120
M8120 is the initialize pulse special internal relay.
When the CPU star ts, the ANST (analog macro) instruction
stores parameters for the analog I/O module function.
The PIDST (PID macro) instruction also stores parameters
for the PID function.
While input I0 is on, the PID instruction is executed.
When internal relay M6 (control output) is turned on, output
Q0 (heater power switch) is turned on.
When internal relay M4 (high alarm output) is turned on, out-
put Q1 (high alarm light) is turned on.
While monitor input I1 is on, the temperature is monitored.
When the temperature is higher than or equal to 250°C,
M10 is turned on.
4095 × 250/1300 = 787.5
While the analog input operating status (D761) is 3 or
higher, M11 is turned on.
When M10 or M11 is on while monitor input I1 is on, Q0
(heater power switch) is forced off and Q1 (high alarm light)
is forced on.
S1
D0 S2
M0
PIDST S3
D100
NO.1
L03AP1
ANST
I0
D1
D102
S1
D0 S2
M0
S3
D100
PID S4
D760
M6
M4
Q1
S
Q0
R
Q0
Q1
M4
I1
REP S1 –
D760
D1 –
M10 CMP>=(W) S2 –
787
REP S1 –
D761
D1 –
M11 CMP>=(W) S2 –
3
M10
M11
I1
M8120