PLC for a beginner

[paul larratt]

Hi dave Eaton Easy plc are really easy to use and set up if you want to chat let me know
My field is automation on many types of systems and yours is anneasy one

 

[Blaspark]

It's cool that there's so many plc guys. Maybe someone could tell me what they think are the best systems with regard to diagnostics and preventing downtime and why?
I really only know about s7 controllers. I'd like to know how the s7 feature with respect to diagnostics and uptime compare to other brands/technologies.

 

[Blaspark]

It's cool that there's so many plc guys. Maybe someone could tell me what they think are the best systems with regard to diagnostics and preventing downtime and why?
I really only know about s7 controllers. I'd like to know how the s7 feature with respect to diagnostics and uptime compare to other brands/technologies.

And how close the languages are to the iec 61131-3 standard for the controllers we're discussing and maybe your preferred language to code in?

 

[timbobelfast]

Trained in Siemens TIA outside of work.

Use Mitsubishi in work with GX works 2.

Like ladder for troubleshooting and prefer to programme in FB. SFC is ok but prefer FB.

Have done some in ST but find it too nerdy for my liking. More like C language that software developers use.

 

[Blaspark]

Trained in Siemens TIA outside of work.

Use Mitsubishi in work with GX works 2.

Like ladder for troubleshooting and prefer to programme in FB. SFC is ok but prefer FB.

Have done some in ST but find it too nerdy for my liking. More like C language that software developers use.

And does diagnostics redundancy type features in the mitsubishi range? Are they there/good/easy to set up?

 

[timbobelfast]

We have a lot of HMIs around the site which aid troubleshooting without having to go into the programme sometimes if a skid is alarming as low pressure etc

The online diagnostics are also very good in GX works. There is a simulator to run programmes to debug offline if required.

 

[Blaspark]

We have a lot of HMIs around the site which aid troubleshooting without having to go into the programme sometimes if a skid is alarming as low pressure etc

The online diagnostics are also very good in GX works. There is a simulator to run programmes to debug offline if required.

What's the network/fieldbus?

 

[timbobelfast]

It's standard Ethernet on a dedicated process network. There are some CC link modules connected as well.

 

[Blaspark]

It's standard Ethernet on a dedicated process network. There are some CC link modules connected as well.

I'm not a fan tbh. I only really know profinet. The features seems exponentially better. Do you have redundancy features?

 

[timbobelfast]

No redundancy features such as slave CPUs etc. Reliability has not been an issue.
They are of course all on a UPS power supply system.

 

[Blaspark]

From what I see it just does redundancy with a loop. It's like profibus.
You have snmp though so not so bad

 

[Blaspark]

No redundancy features such as slave CPUs etc. Reliability has not been an issue.
They are of course all on a UPS power supply system.

You have redundancy available by creating a loop. Obviously I don't know how to set it up since I'm not familiar with you tech and it might only be available with certain hardware. It's available with cc link though

 

[gnuuser]

Im used to allen bradley but have studies siemans and profibus.
they all have decent features.
with slc racks we used in our machines if a cpu failed it was simple to plug a new one in and upload the program to get production going again.
most of the time troubleshooting was simple as you could see the processes on the ladder program, when a function in the machine was not happening, verifying it in the program allowed you to determine if it was in fact the program or the hardware in question.
knowing how the machinery is wired and what inputs and output numbers lead to the components allowed you to diagnose the machinery without . connecting the pc by observing the led's on the cards.
but thats not always the case with multiple machines depending on the training and whatever documentation is there or if it is missing.
its here (automation)where its important that proper training and documentation are stressed. downtime is costly but not as costly as improper safety.
as to writing the programs the absolute number one rule Make sure it is going to be safe to perform that function!

setting up redundant control systems however is a different animal
requiring master control cpus and redundant slaves this would be a complex situation to implement. (not to mention a very costly setup)
For most industrial situations there is rarely any need for a setup such as that (short of a nuclear reactor) and even so the inerrant weakness is one master control and one master output. these points are the weakest links

 

[Bobster]

You have redundancy available by creating a loop. Obviously I don't know how to set it up since I'm not familiar with you tech and it might only be available with certain hardware. It's available with cc link though

Only with S7-400 CPUs can you have redundancy with Siemens so far, they are still working on the S7-1500 to have that functionality.

You can have a profibus network wired in a ring with a suitable ring manager, but this is not the same as redundancy.

Redundant CPUs is not overly complicated to set up, but the cost is huge for the hardware. An then it is only the CPU that has redundancy. In my experience, as long as they are installed in a decent environment, these hardly ever fail. It's usually the IO.

 

[Bobster]

Just noticed a mistake in my post above, I should have said profinet, not profibus.

Profibus can be made into a ring topology, but needs a fiber optics with converters as a backbone, an to be quite honest I have never seen it done.

Profinet is Ethernet based, where as Profibus is a form of RS485 communication.

 

[gnuuser]

Only with S7-400 CPUs can you have redundancy with Siemens so far, they are still working on the S7-1500 to have that functionality.

You can have a profibus network wired in a ring with a suitable ring manager, but this is not the same as redundancy.

Redundant CPUs is not overly complicated to set up, but the cost is huge for the hardware. An then it is only the CPU that has redundancy. In my experience, as long as they are installed in a decent environment, these hardly ever fail. It's usually the IO.

I agree although triacs can handle the higher loads in some system its highly recommended to use fuses or overcurrent devices between the output and coil.
a fuse is very inexpensive insurance against burning out an output module.

 

[SheffSimon]

Just noticed a mistake in my post above, I should have said profinet, not profibus.

Profibus can be made into a ring topology, but needs a fiber optics with converters as a backbone, an to be quite honest I have never seen it done.

Profinet is Ethernet based, where as Profibus is a form of RS485 communication.

I have, in fact I was the one that did it, on a Siemens PCS 7 system. Redundant processors, redundant fibre ring, with redundant copper Profibus links from fibre converter to redundant remote IO processors. At a non-nuclear power station.

But you're right, it's usually the IO which fails.

 

[Automation ATO]

Have a try, you will know it

 

[Bobster]

Have a try, you will know it

After seeing several nonsense postings from yourself. I'm fairly certain this "user" is an AI bot.

 

[Automation ATO]

After seeing several nonsense postings from yourself. I'm fairly certain this "user" is an AI bot.

hello? I can't understand, who is a robot?