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mikecbmc

Processor Speed on V1210

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Hello,

 

Is there any chance Unitronics would consider faster processors options for the V1210.  My programs are constantly growing and am now encountering various issues with scan times.  While I have no clue of what that would entail, it would be great if I could pay for speed options.  Thanks.

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Hi,

PLC most important task is to process Ladder code.

If you need contineous fast drawing, you can split you system into 2 parts:

1.PLC 1 - Minimum drawing, but fast Ladder processing - it may be slowest PLC then you have now.

2.PLC 2 - V1210, used mostly for contineous fast drawing. It's scan time will not disturb for scan time of the first PLC.

And you can use V1210 for other tasks.

What you need to do - organize fast communication between PLC 1 and PLC 2. I hope you will have good working system.

*Fastest CPU is not the better solution, as in most of cases this require re-design.

B.R.

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When you say issues with scan times what do you mean? 10ms? 20ms?  I've run some fairly complex programs and the slowest scan time I've yet to hit was 2ms with ALOT of drawing and updating on a single screen, so checking and updating 3 times/second minimum. 

Keep in mind, on something like the V570, scan time is 9 micro seconds per 1k of application, so it's more likely a programming issue.  It would take near 333k of code for a 9 microsecond scan time to hit 3ms.
 

Some areas you can improve things:

 

1) Look at the calculations you're doing.  Are you doing excess calculations every scan with Longs or Ints, if it's done with a long, can it be done with an Int? If it's done with an Int, do you need it every time?
2) Is it absolutely necessary for everything to scan every cycle?  Some things just don't have a high priority, program around them to limit how often they run.  Can some things be run every 10 scans? 5 scans? 100 scans?

3) Are you using analog in? Keeping in mind most analog in doesn't update anywhere near the same speed as your scan time.  The IO-AI8 in 14 bit mode has a 100msec conversion time, per input.  12 bit mode has 25ms.  So at best you can get 10 or 40 updates per seconds respectively, do you really need to scan it every cycle as well?

 

The biggest three:

4) Are you using a lot of communication protocols and requests? Communications TX/RX protocols can be incredibly slow.  I have a co-working using serial scanning and pattern matching on the RS-232 and his cycle times are routinely around 20-30ms for a fairly simple program.  I've not worked with CANbus or Modbus yet, but there is a potential there to.

5) Are you using a lot of function blocks or sticking to more traditional logic?  Function blocks, while they look simple on the ladder logic, may have many more operations going on in the background to perform their functions.

6) As was said above, how much drawing are you doing per scan?  Lots of dynamic updates can really slow things down.

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Thank you for your ideas.

We are open for everything, what will improve PLCs.

I hope, you can finish your project, when choise right hardware from existing one and optimize its' use.

B.R.

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