How to clear COUNTER content when power is turned OFF ???

[helas]

HI All

I have Omron CQM1-CPU44
I am writing ladder diagram for semaphores
COUNTER, unlike TIMER, don't clear content when power is turned OFF and I need from COUNTER to start count from the beginning the next time when power is turned ON
I don't want to back up COUNTER Area when power is turned OFF !!!
Does anybody know how can I solve this?
banghead

 

[Steve Bailey]

Does your PLC have a built-in 'First Scan' contact? If so, use it to reset the counter. If not create these rungs as the first two lines of your ladder logic.

Continue       First_Scan

---]/[--------------( )-

                 Continue

--------------------( )-

 

[muni]

CLEAR COUNTER VALUE

In counter reset rung,use power on bit and one positive trigger(edge) bit.

bye
Muneeswaran

 

[elevmike]

Like Steve said..on the fist scan, (top rung), load a "0000" into the counter accumelator memory address.

 

[helas]

I did it with built-in function "First Cycle Flag": she turns ON for 1 cycle at the start of operation.

Thank you all, anyway

 

[elevmike]

No Kidding???

Very novel approch!!

 

[BobB]

Use the first scan flag into the BSET function. If your counter area is properly organised, the BSET (blockset) function can be used to set a whole data area (you specify the area) to #0000. The # symbol represents constant, and will write 0000 (BCD) to the specified area.

Vey usefull old instruction. Has been available since about 1992 or 3.