Can I initialize PLC when it power on/off in Unity Pro S

timcph2008

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Hi guys, I want to initialize PIDFF controller when PLC power on or off.

I know that to reset the PIDFF, I need to trigger TR_S, and I try to use system bits %S13. However, it only reset the PIDFF when the PLC run/stop, not power on/off. Because when I power off the PLC, it still remain run after I power back on.

Do you guys have any idea?

Thank you for your help!
 
try system bits %S0, S1 and system word SW10.0

%S0 cold restart, normally "0" state
%S1 warm restart, normally "0" state
%SW10.0 first cycle after cold start (mast cycle, normally "1")

- put all to or block (%S0, S1 directly, %SW10.0 with invert) -> plc started bit??
 
Last edited:
Update: Sorry I forgot to set the input back to 0 when I use Reset-Set function block for testing... %S1 actually work, sorry for the stupid mistake
 
Last edited:
bits are "1" or "0" state only one scan. Maybe you need to add timer for resetting block. (Not sure if block needs "1" signal for several scans.)


Checked from program. Attachment's ton timer output will be "1" after 60 seconds of PLC start.



Note from help files:

"%S1 is not always set in the first scan of the PLC. If a signal set for every start of the PLC is needed, %S21 should be used instead"

start.jpg
 
Last edited:
Lare said:
bits are "1" or "0" state only one scan. Maybe you need to add timer for resetting block. (Not sure if block needs "1" signal for several scans.)


Checked from program. Attachment's ton timer output will be "1" after 60 seconds of PLC start.
Click to expand...


Yes I need a timer for extend the signal. thank you!
 
Lare said:
bits are "1" or "0" state only one scan. Maybe you need to add timer for resetting block. (Not sure if block needs "1" signal for several scans.)


Checked from program. Attachment's ton timer output will be "1" after 60 seconds of PLC start.



Note from help files:

"%S1 is not always set in the first scan of the PLC. If a signal set for every start of the PLC is needed, %S21 should be used instead"
Click to expand...


I try used TON, however. However, %S1 and %S21 set to 1 at first scan then reset to 0. TON is on delay, seems we should use TOF instead TON for extend the %S1 and %S21 signal.

%S1.png
%S21.png
 
Yed. Example which I posted delays start 60s on warm and cold restart. Ton Output is off 60s seconds after plc start.
AND block's output is "0" at first scan -> Ton timer start count time from second plc scan)


You can invert ton timer's output, so then bit is on when plc is started and off after 60s from plc start.

If you change timer, then you need invert and-block's output before TOF or TP-timer.
 

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