PLC for a beginner

[davesparks]

7 months on and the job is finally happening!

The first stage of the job has happened, the old control system is out and the new panel is in, I've got all the existing circuits working and returning next week to start the next stage of adding the new elements to the system.

I opted for the Siemens s7-1200 PLC and managed to get the hang of writing very basic ladder logic programs pretty quickly, or at least enough to get lights to come on when buttons are pressed.
And the bonus was that the program actually works!

I will update this thread as the job progresses and I'll try to get some pictures so you can all take the ----

 

[telectrix]

any useful info you can pass on regarding PLCs will be appreciated, digested then discarded. old dogs, new tricks etc. .

 

[timbobelfast]

Sounds promising, are you using TIA step 7 ?
What's the panel controlling?

 

[davesparks]

Sounds promising, are you using TIA step 7 ?
What's the panel controlling?

Yes, TIA portal step 7 which came bundled in the starter kit.

The panel is controlling lights. Specifically the backstage working lights in a theatre.

Control of these lights is via a master pushbutton station with some zones having their own local pushbutton stations. There is going to be a button at stage door to provide a last out / first in function. And also this system will incorporate 'grid beacons' which are flashing beacons to warn people of overhead work, this includes a sounder which will give a 3 second tone when the beacons are switched on and a different tone when they are switched off.

So it's very basic stuff as far as the PLC goes, but a good learning experience.

 

[gnuuser]

Sorry for sounding like a dehngis but what exactly is a PLC?
I noticed Trend mentioned above I’ve done some work with their systems iq3 xcite and the 963 front end on BEMS is PLC just another term for that or am I barking up the wrong tree?

a plc is a programmable logic controller ( as small real time automation control computer used in many pieces of industrial equipment such as conveyor systems, packaging equipment, or any process you want automated)
a plcc is a programmable logic controller computer! This is a dedicated computer permanently connected to a plc system to manage and program multiple networked plc, slc's and vfd controller banks found in motor control cabinets.

plc and slc systems use ladder logic programming and sometimes panel view for simple interface programming using block diagrams

 

[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.