timer conversion

[Prayder]

I am converting a micro 1000 program to studio 5000 and I was wondering about the time base factor. In the micro RSLogix 500 program some of my time bases are set for 1.0 and 0.01 but i was wondering how to do that in the Studio 5000 software.

 

[Narlin]

IF YOU HAVE TIME IN SECONDS,SAY COMING FROM AN oit INPUT, THEN MULTIPLY IT BY 1000 AND MAKE THE DESTINATION THE TIMERTAG.PRE
eg. MUL ALARM_DELAY 1000 DELAY_TIMER.PRE

 

[Prayder]

I apologize but still kind of new to this so not exactly sure what you are referring to....

 

[Narlin]

The time base for a timer (TON TOF etc.) in Studio 5000 is milliseconds. Basically you have to deal with it. All timing is in milliseconds.

 

[Prayder]

let me ask you this:

In one of the TON I have a time base of 1.0 in the RSLogix 500 program with a preset of 5. So I am assuming that in the Studio 5000 the TON preset would be 5000 since it automatically counts in milliseconds?

 

[Narlin]

That would be right. Studio 5000 helps you less.
Wait till you find out that the SCP instruction is gone!

 

[Prayder]

Hey thanks man... I really really appreciate the help here!

 

[Operaghost]

This is probably more than you can to know, but what the heck....

The older PLC/SLC/Micro controllers were 16-bit so they had to deal with a maximum number limitation of 32767. The time base was a way to work with this rather limited range. It wasn't a good thing, it was just what we had to do.

With a time base of 0.01 seconds you could time up to 327.67 seconds. The real benefit to this base was that you were given two decimals. So for example you could have a timer that timed to 21.67 seconds. The limitation though was that you could only time for a little over five minutes.

With a 1.0 second time base you can time much longer. Up to 32767 seconds (a little over 9 hours), but you lose the ability to have sub one second resolution. So with a 1.0 second time base I could time to either 21 or 22 seconds, but not 21.67 seconds.

Some controller also had a 0.001 time base option which would give us three decimals to work with, but we would be limited to a maximum of 32.767 seconds.

There are of course ways to get more time, usually by using a counter.

The Logix 5000 family times only in milliseconds but as it is a 32-bit controller it can time to over 2 billion milliseconds (just short of 25 days). So the Logix controller drops the time base not because it doesn't support it, but because it doesn't need it.

The previously mentioned SCP instruction is available as an Add-On instruction with the included Sample Code. There are a whole bunch of Add-Ons that are included and more that can be downloaded from Rockwell's Sample Code web site.

OG

 

[keenan01]

Nice thread, I also have the same problem

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