PLC Timing

[denise01]

Hello Am trying to turn on a output at one minute to six in the morning. It has to be precise. Does any one know the best function to use to do this The PLC is a CJ1M. Many Thanks Peter

[Michael Walsh]

Use comparison instructions (=) with addresses A351 and A352. A351 = MMSS where MM is minutes in BCD format from 00 - 59 and SS is seconds in BCD from 00 - 59 A352 = DDHH where DD is the day of the month in BCD 01 - 31 and HH is the hour in BCD from 00 - 23 You will need to mask out the day of the month. Something like the code below would work:

[denise01]

Many Thanks Michael, I have used the compare functions and the clock functions in the past but never knew how to get a precise time. I am devising a production count to work in association with Supervisor and put three totals up on to a over head monitor this will help me considerably because my PLC clock timings seem to change sometimes. Any way thanks again Regards Peter

[BobB]

The time clock in the PLC is not extremely accurate over time - I would suggest you use an external precision time clock that can be than can be set bu anyone at any time.

[PdL]

If the PLC is equipped with an Ethernet unit, you can sync the RTC with a NTP server...

[denise01]

No unfortunetly I link the CJ1Ms by Hostlink, which I think accounts for some of the problems with time. I maybe need to alter the scan time. Regards Peter