What is MAST, FAST, POST and PRL?

  • Thread starter Will Brokenbourgh
  • Start date
W

Thread Starter

Will Brokenbourgh

I have been working with ladder-line for the last five years, and have just recently become a control tech, mainly self-educated. I have used and programmed AB PLC-2, PLC-5, and MicroLogix, as well as Omron C200H, CP1, etc.

Recently, I have had the displeasure of adding the Telemecanique TSX Micro and TSX 17 to my experience list. Can anyone explain to me why I need all of these different modules such as MAST, FAST, POST, PRL, CHART etc? What are their functions? Is it really necessary to break up the program like this?

As most of you have probably gathered, I don't have the resources or time to take training or do extensive research on this matter. I'm 'comfortable' with AB and Omron's 'all in one' type programming, I just don't get this schizophrenic-type language (GRAFCET is it?)
 
R

Ranjan Acharya

<clip>
I have been working with ladder-line for the last five years, and have
...
...
just don't get this schizophrenic-type language (GRAFCET is it?)
</clip>

What you are referring to is in the direction of IEC 1131.3 or 61131.3. There is a book by RJ Lewis available through the IEE or IEEE that will
assist you.

Unfortunately the newer software tools are a lot more difficult to use and require at least some training. I would recommend vendor-specific training through Tele.

However, that being said, they give you much more power and provide things such as a non-linear scan and the ability to move away from Ladder Logic. Ladder may be very popular here in North America, but you cannot solve everything with Ladder and if you want to sell a product in Europe (and elsewhere), your customer may balk if you try and user Ladder.

Unfortunately 1131.1 is a manufactures' standard rather than a users' standard and so, despite the original intention, code written for one brand
of automation controller (PLC) is not portable to another.

To put things bluntly, get used to it. This is the way things are going. Pure Ladder has its place, but there are alternatives and we all have to get used to them.

RJ
 
G

Gilles Habel

> Recently, I have had the displeasure of adding the Telemecanique TSX Micro and TSX 17 to my experience list. Can anyone explain to me why I need all of these different modules such as MAST, FAST, POST, PRL, CHART etc? What are their functions? Is it really necessary to break up the program like this? <

MAST=Master task, FAST=Fast task
The fast task can interrupt (based on time or events)the master task to react quickly.Those 2 task are usually program in Ladder

The PRL, CHART and POST are sections related to Grafcet. If you don't want to use this sequential language, you can forget all those sections. But, if your problem is a sequential problem, you will not take full advantage of a very powerfull programming and debugging language. PRL is a Ladder section executed before the CHART (the section where you draw the Grafcet); POST is a Ladder section executed after the CHART.

> As most of you have probably gathered, I don't have the resources or time to take training or do extensive research on this matter. I'm 'comfortable' with AB and Omron's 'all in one' type programming, I just don't get this schizophrenic-type language (GRAFCET is it?) <

If you have a sequential problem to solve, you should spend an hour to learn how it's works...
It's easy and very powerfull...

GH
 
Top