Modicon M340 system a good choice ?

[OkiePC]

I have also found it common for specifying engineers to only want code done in Ladder which disappoints me. Do they want it dumbed down so electricians can read it?

I think this is 90% of it the other 10% being licensing...I know with Rockwell stuff you gotta pay extra for each language or buy them as a package, and the price is quite high.

Instrumentation guys and "true" electronics people absolutely love FBD if done well. I know nothing about Schneider stuff, we have a machine using an M340 on lease with remote monitoring by them. In six years, they've not asked me to do anything with the PLC. We have lost a VFD or two over the years and the HMI screen (out on the wash down floor) occasionally eats a power supply.

The hardware must be good, and the electrical protection is overkill with circuit breakers for every discrete point, because I have never been asked to go look at the PLC, replace a card, etc....and if they had a problem they couldn't see remotely, I would be the guy they call to go check it.

 

[BobB]

I have also found it common for specifying engineers to only want code done in Ladder which disappoints me.

Does not disappoint me when I have someone on the phone 3000 Klms away and I trying to troubleshoot over the phone. FB is too hard for them and ST makes it worse - I have no desire to get on a plane, travel 1 day getting there, work for 1/2 hour sorting out the problem and the travel 1 day getting home - I can be more gainfully employed than that. 3 days lost! Usually leave home @ 4AM and get home near midnight for the trip too - hate sitting on planes and in airports - cannot get anything done - waste of time.

If facilities would only give their electricians more PLC training and exposure to IEC languages, they would then not want to go back to inefficient ladder.

Does not help when they are in the 'never never' to be honest - training would not help - they would be lucky to see a PLC program once every 5 years. I have to get them to check things and sort it out myself.

Instrumentation guys and "true" electronics people absolutely love FBD if done well.

I do not agree - I am an instrumentation engineer, electrical engineer, electrical fitter, management degree, marketing degree - I can write software much quicker in ladder - copy and paste. The only time I ever use FBs are when I have regular routines - that happens once in a blue moon - it would take me twice as long to write FBs. Time is money when you work for yourself! Software hold ups cost me money - I have tried FBs in 4 brands of PLC so far and have gone back to ladder - far quicker - make more money to buy 'good' red wine.

Licencing fees are a joke - my understanding with AB is that there are several sections in the company, one writes the software, one distributes the software to other divisions, the sales division then sells the software/licences - a mate of mine works for them and that came from him direct. They all make a substantial profit on the way. Schneider want over $3000 per annum to keep their software up to date - Siemens and many others are no better.

With my favourite brand I pay about $750 for a major upgrade every 18 months/2 years and all other updates are free. That is the whole package too - drives - networking - screens - motion - the lot. Cost effective and I make lots of money from not wasting time doing 'pretty' things.

I would still like to know if Schneider have standard functions for floating point though, I have a job coming up with an M340 - would like to know if I have to use infernal FBs or not.

Sorry about the rant! When you work for yourself you look at ways to make money - not do elegant things.

One thing I may add here - I write software for other people but do not commission it - they do. I always have to write software to suit the lowest common denominator - my client. I have trouble getting these guys to understand a bit counter - let alone a reversible shift register! Phone goes off regularly - drives me nuts sometimes.

 

[GTUnit]

Another thing I have found of late is that some electrical consultant engineers are writing into the specification that all programs MUST be written in ladder - no other languages allowed.

This kind of thing is irritating...
The reason to write using several languages is because certain logic can be written in a clearer, significantly simpler, and more efficient manner in one language versus another.

 

[GTUnit]

Did you use the io scanning capability in the M340 - only need to fill out a line in a table in the plc, set the ip address of the drive (can set the drive to a fixed ip or use the plcs dhcp server to assign an address), and job done - the drive data will be available in the assigned addresses

The particular rack I was tasked to program only had the Ethernet port on board the processor. As far as I know this does not have the IO Scanner capability.

If the guys designing the system had included the Communications module then I would have had IO Scanner capability and my life would have been much easier.

 

[BobB]

This kind of thing is irritating...
The reason to write using several languages is because certain logic can be written in a clearer, significantly simpler, and more efficient manner in one language versus another.

Agreed but there is still the lowest common denominator to be considered as well.

 

[GeoffC]

I remember the one that annoyed me most was floating point maths had to be done in an FB with ST - has that now been put into ladder as well Geoff?

Not sure what you mean I have always been able to do floating point maths in ladder. I have attached an example
ps - this is a rung in Ladder. In ladder you can use any of the predefined functions or any of the functions you may write yourself

 

[BobB]

That's a bit funny Geoff - I had the Schneider software guru visit me and he told me it was not possible and had to be ST in an FB. Young guy but supposed to know his stuff - obviously not! Thanks for that - feel a bit more comfortable now as the program will have to be in ladder - consultant!
Hard to get good help sometimes.

 

[GeoffC]

No worries - see my edited post above using an interlock in the maths

 

[BASIC ELECTRICAL TEC]

Thanks to everyone for all your input.
I finally got to a real tech person for Schneider on my own.
Meeting with him on Monday.
Bruce