Versamax PLC -- On/Off timer

[RioPLC]

I have a versamax PLC and I am trying to write some ladder logic in Proficy Machine Edition that will turn an output 30 seconds ON then 30 seconds OFF repeated for 12hours

I cannot use TMR_SEC with versamax

If anybody can help me that would be appreciated.

Thank you

 

[Steve Bailey]

The VersaMax has a %S bit named T_MIN. It is on for 30 seconds, off for 30 seconds, on for 30 seconds etc. Once you have started using it to control your output, each time it turns on, increment a counter. When that counter reaches 720 you will have counted 720 minutes (12 hours).

 

[RioPLC]

I am using this to send a COMREQ command to turn my power source on for 30s off for 30s ..

I think #T_MIN would be better if I was flashing a light.

Is there a way to do this with a timer that I can start, rather than #T_MIN starting on powerup.

 

[Steve Bailey]

The T_MIN bit doesn't care whether the output it is controlling is a lamp, a contactor or anything else. You can set an internal bit true when you want the T_MIN bit to control the output and turn the internal bit off after 12 hours. Use a NO contact form the internal in series with the T_MIN bit to control the actual output.

A method I have often used when I run up against the limitations of a 16-bit timer is to use a timer that resets itself when it reaches its preset. When you do that, the timer's "done" bit is true for one scan and can be used to increment a counter. For example, create a timer that resets itself every six seconds and use it to increment a counter. The counter's accumulated value is tenths of a minute. Twelve hours is 7200 tenths of a minute.

And what are you turning on and off with a COMREQ? You could have the T_MIN bit trigger a one-shot which triggers the COMREQ.

 

[parky]

Why not use two timers of 30 sec duration
AN T1 an C1 out T0 300
A T0 Out T1 300
A T0 C1 720
AND T0 Out Q1.0 //Turn on output every 30 secs for 30 secs
On power up T0 starts to time, when preset is reached it starts T1
so T0 will be off for 30 seconds then on for 30 seconds.
(30 second flip flop), then use contact off T0 on a one shot to increment a counter preset to 720 will give you a time span of 12 hours you could use the counter up to disable T0, this would start/stop what ever you want on a 30 second on 30 second off, after 12 hours it will all stop, then you need to reset it to start it again you said you want this to happen for 12 hours what then ?.

 

[RioPLC]

I want to move ASCII string OUTPUT ON to register and send the COMREQ to transfer this string over Port 1 rs232 to my power source.

Then after 30seconds I want to move my ASCII string OUTPUT OFF to register and send the COMREQ

So I just need to go back and forth triggering on and off every 30s

Power on 30s Power off 30s Repeated for 12hrs..

I have the string and comreq sending correctly but am having trouble with the on/off timer.

 

[parky]

See below, although this is done in GX Developer & symbols are different.
Timer 0 times out after 30 seconds, this starts timer 1 and also pulses the send on request bit (M0), then increments the 12 hour counter. T0 Stays on allowing T1 to start timing, after timeout it pulses the send off request (M1)
On next scan T1 is on so it resets T0, and of course T1 as T0 will be off.
This repeats until the 12 hour counter has reached it's preset value and disables T0, this stays disabled until the 12 hour counter is reset.
You could use a pulse bit off the timers to set the send bits, resetting them after communication has be sent.
Just realised that I put a low value on counter preset, this should be 720.

 

[RioPLC]

I have it working now, Thank you for the help!!