Schneider Modicon M241 and SoMachine v4.1

[HamzaSA]

Hello everyone,

I just stumbled upon this site and it looks really interesting! This is my first post here.

I have never programmed PLCs before, therefore I am a complete beginner but I'm a quick learner. My first task is programming a m241 with ht eSoMachine v4.1 software. I have added the devices that will be used and made the majority of my POU.

However, I am confused with the memory mapping. I understand data types (bits, bytes, words, dwords etc) and I understand that the syntax is %MX, %MB etc. But from where can I start allocating memory? From what I understand there is also system reserved memory so it probably has a portion of memory reserved (bear in mind that I still haven't been able to read the entire self-service manual).

For example, I am measuring temperature over a sensor which is conncted to the analog input. I want to store that data inside a virtual variable so it can be accessed remotely.

Also, function block instancing isn't completely clear to me. I made a function block which receives an INT from the sensor and converts it to REAL. When I insert the block inside POU, I get "???" over it. I don't understand what this "???" means or how I should remove it.

I realise I have a lot of knowledge gaps with PLC programming and I am grateful for any help you can provide.

Thanks in advance,
Tarik

 

[chud]

Sorry for the short reply and not answering your direct questions but it would be a lot easier for you to go through this manual.

Click on the link and open the pdf

http://www.schneider-electric.co.za/en/faqs/FA288633/

 

[gclshortt]

Getting Started With SoMachine - Self Study Manual
http://www2.schneider-electric.com/resources/sites/SCHNEIDER_ELECTRIC/content/live/FAQS/288000/FA288633/en_US/Training%20Manual%20EN.pdf

http://www.filkab.com/files/category_files/file_3079_bg.pdf
Chapter 5 - Memory Mapping

The above links may help you out.
Regards,

 

[kittydog42]

You don't have to allocate any addresses to the variables. It will allocated memory space automatically. The only reason that you may choose to manually assign a address such as %MW100 is so that you can communicate to the PLC with an HMI using Modbus.

Read up on CoDeSys - SoMachine is a just a different front end for the standard CoDeSys programming software.

 

[Engineer_MG]

Hello everyone,

I just stumbled upon this site and it looks really interesting! This is my first post here.

I have never programmed PLCs before, therefore I am a complete beginner but I'm a quick learner. My first task is programming a m241 with ht eSoMachine v4.1 software. I have added the devices that will be used and made the majority of my POU.

However, I am confused with the memory mapping. I understand data types (bits, bytes, words, dwords etc) and I understand that the syntax is %MX, %MB etc. But from where can I start allocating memory? From what I understand there is also system reserved memory so it probably has a portion of memory reserved (bear in mind that I still haven't been able to read the entire self-service manual).

For example, I am measuring temperature over a sensor which is conncted to the analog input. I want to store that data inside a virtual variable so it can be accessed remotely.

Also, function block instancing isn't completely clear to me. I made a function block which receives an INT from the sensor and converts it to REAL. When I insert the block inside POU, I get "???" over it. I don't understand what this "???" means or how I should remove it.

I realise I have a lot of knowledge gaps with PLC programming and I am grateful for any help you can provide.

Thanks in advance,
Tarik

Hi,

You don't need a function block for INT_TO_REAL.

Just type INT_TO_REAL (it's a type conversion operator).

In SoMachine -> Help -> SoMachine programming guide -> Programming reference -> Operators -> Type conversion operators.

For an understanding on what a function block is SoMachine programming guide -> Program -> Program components -> Function block


Hope this helps.

Thanks.

 

[HamzaSA]

That's exactly why I want to give it an address kitty. After some testing, I realised I can even assign %MD0 for REAL values because it doesn't seem to be reserved, but just to be sure I'll start my memeory allocation from %MD100

Engineer_MG, I realise there is that block, but I want I wanna make a FB that will convert the INT value from Ni1000 sensor to REAL then divide it by 10 to get the actual temperature which I will use to display etc. I wanna make a FB to do it, and not use INT_TO_REAL in series with a DIVIDE block.

 

[Engineer_MG]

Create a function

- You can create a FUNCTION to encompass your equation(not Function block).
- Please check attached images as an example
- A function has one return type and does not need to be instantiated
- Keep in mind the divisor should not be zero.
- If you create a Function block, it will need to be instantiated when calling it.

Hope this helps.
Thanks.

That's exactly why I want to give it an address kitty. After some testing, I realised I can even assign %MD0 for REAL values because it doesn't seem to be reserved, but just to be sure I'll start my memeory allocation from %MD100

Engineer_MG, I realise there is that block, but I want I wanna make a FB that will convert the INT value from Ni1000 sensor to REAL then divide it by 10 to get the actual temperature which I will use to display etc. I wanna make a FB to do it, and not use INT_TO_REAL in series with a DIVIDE block.

 

[HamzaSA]

Ok, I figured it out.

Another question, what is the best way of controlling a three-way valve? I thought about implemention a PID controller, but couldn't find a 3-state one in SoMachine, only continious.

For controlling the valve, I only have 2 BO's available, for opening and closing.

 

[Engineer_MG]

Ok, I figured it out.

Another question, what is the best way of controlling a three-way valve? I thought about implemention a PID controller, but couldn't find a 3-state one in SoMachine, only continious.

For controlling the valve, I only have 2 BO's available, for opening and closing.

Look into OSCAT.de. The OSCAT libraries can be installed in SoMachine.

http://www.oscat.de/component/jdownloads/send/5-oscat-building/27-oscat-building100-en.html?Itemid=0

They have some cool function blocks (Maybe you can use the Actuator_3P from the OSCAT building library if that's what you are looking for).

Thanks.

 

[HamzaSA]

Yeah, that looks like it might work. I'll try it and report back. Thanks for the help so far