Mimic panel

Hi guys,

I am trying to create a mimic panel so that we can see what is going on with the plc and the process. At present the plc controls 15 solenoid valves, there are also pressure switches and temperature probes that feed signals back to the plc.

I was hopeing that with care it could be possible to tap into these lines and create the mimic panel. I want to be able to put lamps on a panel that looks like the mechanical drawings so we can follow the sequence of events.

I then want to create another panel that can be placed in a production hall so the opperators can see where in the process it is and if there is a problem then we could see where the problem ended.

so for each valve that opens I want a light to come on and when it has closed again stay on until then next light (valve) opens.

I am a novice at all this and I'm not sure if the plc can handle it. the master plc is a FXon-40ER and the slave is a FXon-40MR.

Can anyone suggest how I would go about this, or give me some guidance please.


Thanks

Cindy

The easiest way to do this would be with a graphical HMI. This would let you match the drawings or even better what the actual process looks like. Using an HMI or screen would allow you to put it virtually anywhere by just running communication wiring. Using a panel with lights would require a whole lot more wiring but could be done, depending on distance and time spent I am not sure the cost would be any less either.

Here are some choices:
http://www.maple-systems.com/

http://www.exor-rd.com/home.asp

EZ Touch

GE QuickPanel

Hi Cindy,

What you want to do can be done. BUT there are at least a couple of things to be careful of:

1) As you suspected, each sourcing output is limited to a maximum current it can supply. If you parallel lights with your valves, you could easily overload any given output. Depending on your PLC, you could even overload an entire group of outputs.

2) By doubling up devices on a single output you risk complicating your system and adding potential downtime. For instance, if one of you indicator light wires was to short out, you would a) create downtime because the valve would also be out of commission and b) you would have to check both light and valve wiring in order to troubleshooting your process.

If you still want to create a hardwired indicator panel rather than the graphical HMI like Ron suggested, look using a relay as the load for each of your outputs and then run your valve off of one set of contacts from the relay and the indicator lights off of another. This would also allow you to use separate power sources for the valves and lights and even different voltages.

As Ron said, the cost of making a hardwired indicator panel is pretty high and may end up being more than the cost of installing an HMI. I use a rule-of-thumb of $100 per light / pushbutton / selector switch when figuring the cost of building this kind of panel. While this number may seem a little high, it generally takes into account the cost of the enclosure itself, internal wiring, and labor.

Steve

thanks

I have had a look a the sites you suggested and I think it is a great idea! But.... I am not a confident programmer and I wouls think you need to be able to do that to be able to use an HMI. If I am mistaken and it is not as complicated as I think then please correct me. I can not afford to harm the current system in any way as I would deffinatley be sacked!! production runs 24/7 and they would loose 100s of thousands if I broke what we have.

Can I obtain a manual to be able to learn it before I purchase it? normally they dont give you that stuff unless you buy it first.

Cindy

Yes, there is a bit of a learning curve to programming any HMI, but I think you would be surprised how easy it ends up being.

The really good thing about virtually all HMI's is that they are passive to the system. This means that the system will function uninterrupted if the HMI is off line. This lets you do what you want without affecting the PLC's operation. The real joy of all this is that all your HMI programming itself is external to the PLC.

Now keep in mind that at some point you will have to interface your HMI with the PLC. This might mean that all you have to do is find an appropriate interface port on the existing system (generally the processor) or you might have to install a new interface module on the PLC (Ethernet, for example) and reprogram the PLC to accept it and talk to it. If a module install is required, it is usually a pretty straightforward procedure.

Steve

What type of Solenoid valves are you using?
I was just wondering if they are at all visible on the equipment.
You may be able to replace the connectors with new ones that have LED pilots built into them.
This way you can actually see if the Valve is being energized or not.
The picture is of a Numatic Air valve, I know it's hard to tell, but the gray connector actually has an LED built into it, and it glows when the valve is energized.

Programming the HMI is going to be easier for you to learn and much faster than designing the graphic board with the interlocks and wiring and so on. That is why graphic boards are almost obsolete.

Your best bet is to contact the local distributor for the brand of PLC you are using. Tell them you want a graphic touchscreen for interfacing with Model "X" PLC. They will be happy to come in, do a demo of the operator inerface, show you how the software works, and will be available for technical support when you run into problems.

The simplest method is to use LED's to mimic the operation of the valves.
The LED's can be mounted in a panel, with the plant layout engraved onto it, and the LED's inserted at the appropriate places.
The use of LED's is unlikely to overload the PLC outputs, although make sure they are rated correctly for the output voltage.
It would also be possible to mimic the PLC inputs by using this same method.
This is a very basic method of displaying the plant status, but if you have little experience, it is a good place to start.
I hope you achieve what you want, and as your experience gives you confidence, you will be able to move into HMI's and maybe SCADA systems.
Good luck.

An HMI is the way to go if you want to show what is happening.

They are passive if you dont program any button functions to operate within the plc program.

You can just use the buttons to show different screens or you can make events within the plc automatically change to the appropriate screen page.

You can design your own graphics and have them on the screen to show just what is happening and of course, it is a good excuse to get some good learning in.

You can program the HMI live while it is plugged into the PLC and know that you are not going to affect the workings of the PLC.

One of these days I will learn to take my time to reply thoroughly.

Can you wire a panel and attach lights (of some kind) to the existing outputs....YES Could you use another set or inputs and outputs to match the existing just to drive the lights to mimic the process...YES

As has been stated this may not be most efficient or cost effective way to do it. Look at time it would take to build your mimic panel(s) and the number of people that would be needed to do what you propose. Also note that to do this the machinery MUST be down to do the tie ins for the wiring regardless of the way you decide to do it, look at how long it would take to do this wiring and adding any relays that may be needed.

As was stated also talk to different reps about HMI units, in many cases they will initially help you setup the first unit to a working point and you can modify as needed. The good point of using an HMI is that you wouldnt have to run alot of wires, normally just power and the data cable. Another good point is that they can easily be placed up to 4000 feet in most cases using just two wires. RS232 units can be adapted to RS485 and back to RS232 for around $100 US. We are talking minimal wiring and possibly no conduit needed (except for power wiring). Once connected, very minimal downtime if any, you can modify as needed in many cases. Thats where its nice when the HMI has 2 ports, one to connect to plc and another for programming.

I have done many panels like you described over the years but HMI's offer better graphics that make understanding the process so much easier AND if you dont have ALARMS on the system in time you can add ALARMS, depending on the HMI this may not require any plc programming. Most HMI's offer so many features and options it would be rare for me to go back to using a panel for this kind of project.

Another point is it gives you the opportunity to learn some form of programming without actually having to do any programming in the PLC at this time. As was stated its a good opportunity to learn, give it a go.

One more thing, using newer devices like HMI's etc make you look more advanced than you may truly be BUT never let anyone know otherwise.

IMHO, a SCADA system such as Citect would suit your needs better than an HMI. With the above mentioned system, you can go online for 15 minutes at a whack, all with a free download. You can draw your machine as you wish, represent any I/O as a indicator or what not, etc. Just a thought.

My two cents--The OI panel is the better solution, in my opinion.

But if you end up doing a pilot light panel, use outputs for all the lights--do not use the solenoid power or limit switch feedback to energize the lights. By using seperate outputs for lights and lights only, you have the opportunity to include a "Lamp Test" feature. It simply switches on all the lights to verify that they all work, without altering the process.

I wish I had a nickel for every time a burnt light bulb steered me toward a problem that didn't exist and wasted my time. Indicators are great--but only if you know they work properly.

I support the resounding cry for using a HMI screen.
It not only would give you the opportunity to enhance your skills and marketability but it would make use of your existing signals. Hardwiring a couple of graphic panels would be more costly in the long run and would create new sources for problems.

Roger

Thank you all

I appreciate all the advice guys, I think I will go with the HMI it sounds like the better option. If I need to interface with the current plc program I will have to get in a plc engineer because we dont even have the facilities to run the software on a pc. I have the program on disc but thats not much help. I will aslo contact a local HMI dealer hopefully they can point me in the right direction and provide the support I know I will need.

I will post another mail when all this is done to let you know if I still have a job or a pay rise.


Thanks

Cindy

The HMI is the way to go. It would be easy to have an HMI display inputs and outputs, all you have to know about the PLC for this is their data table address's. That could be step #1. Then as you learn more about the PLC and the HMI, you could start adding screens that are more graphical of the machine itself. Eventually you could add troubleshooting routines which tell the operator and maintenance which valve has failed, what limit switch failed, if something is over-temp or an overload has tripped. To management, this looks like magic!! This way you can take it slow and build upon what you are learning. Been there, done that, and lived to tell about it..