EZ Touch Screen Problem?

Ok using a EZ Touch screen (10" color) and having a problem on my main screen I have set of 4 inputs to start and stop machines. What I am seeing is the start button (momentary on) stays on after it is pushed. Doesnt do it every time but sometimes.

My boss it is in my ladder logic, but I think it is a touch screen malfuction. Has anyone ever came up with this problem

here is an example of my code

B4140.0 B4140.1
Touch screen Touch ScreenTouch
Momentary On Momentary On
START STOP Motor #1
[---II--------------I\I------------------------(C0)--]
l l l
l l l B4243.1
l C0 l l Touch Screen
l-II-l l Indicator Light
l----( )--]

I can't quite follow your code but I just use C bits for contacts. (C100, C101, etc.). I'm not very familiar with the B bit addressing anyway.

Sid

I don't have it here, but I remember a little disclaimer or alert that comes with the unit. I don't remember exactly but it has to do with momentary buttons. See if you can find it in your documentation.

tommy23t

Joe,

I remember that the EZ-Touch has 3 or 4 different settings for the pushbuttons. I think they are momentary, maintained, panel set-acknowledge reset, panel set-PLC reset. If you have your buttons set to momentary, and the START button stays on after release, then probably the button is sticking.

Where one button is sticking, I have modified my program to use one of the other (working) buttons for the critical functions such as Start and Stop, and used the sticking button for other things such as to set the clock time, or the date, or to set the time on a timer. If it sticks sometimes for these things, then it is no big deal. But when you hit Stop, you want things to Stop!

jrwb4gbm said:

I can't quite follow your code but I just use C bits for contacts. (C100, C101, etc.). I'm not very familiar with the B bit addressing anyway.

Sid

Click to expand...

About a year ago, I had a problem with B bits. If I remember correctly, I couldn't turn them on and off, but set/reset worked. I reported this to AD. I was trying to start a PID loop. A oneshot on a OUT coil didn't work. I had to do a SET.
You can read B bits okay. My problem was within the program - I wasn't trying to do it with the touch screen, but it doesn't matter. Just suffice to say I did see a problem with B bits.

The correct solution is to use C bits. I've never seen other problems, including the issue you describe. The program is about 400 lines long, 260 processor, 2 racks, 12 PID loops, and 20 screens. We started with a 6 inch mono, and upgraded to an 8 inch color as the program grew.
The processor is very busy, but I've never seen a glitch.
Aside from the minor B bit issue, I give AD a perfect score.

Lancie1 said:

If you have your buttons set to momentary, and the START button stays on after release, then probably the button is sticking.

Click to expand...

So it is possible for buttons to stick, if so then is it a malfuction witin the screen? If it is wont it effect other screens with objects in the same area?

90 percent of the time when a momentary pushbutton on a touchscreen "sticks" you are having communications problems. The touchscreen writes the "on" value fine (communications is good at this point), but when it tries to write the "off" value it times out and never gets written (communications is bad at this point).

This is a very common problem. Most of the time you will never know if you are having occasional communications problems, but momentary pushbuttons are a sure way to find out.

While it is possible that the screen is actually sticking it is highly unlikely. It also could be your program, but then if it works most of the time, it probably isn't.

Did you make your own communications cable or extend the factory cable?

Are there any devices that create large magnetic fields such as welders, transformers, contactors, VFD's, etc nearby?

Are you using the power supply that powers the touchscreen to power any sort of coil device (relays, contactors, solenoids, etc)?

Any of the above could cause communications problems.

I have to agree with icky on this one. Look for some communication problem somewhere. I use a lot of the EZ-TOUCH screens and the one thing they are notorious about is not liking electrical noise. When I've had momentary buttons that 'stick' it has always turned out to be bad communications between the EZ-T and the PLC.

I've had "stuck buttons" with RSView32, PanelView550, and PanelView1000 products. Because of problems like this one, I have developed these two practices:

1. Design the logic to require false to true transisitions of the button addresses to initiate motion or state changes.

2. Reset/unlatch the HMI pushbutton addresses in the PLC after all logic referring to them is scanned.

Usually the PLC code can be constructed to cope with the problem without any difference in the operation of the machine. Both methods improve safety. The machine won't start unexpectedly. The first method leaves the HMI address alone so you can see what the HMI is doing while on-line monitoring. The second method makes it harder to see the action of the button when online monitoring, but will allow things to operate as normally as possible in the presence of communication problems. If the address is updated by the HMI synchronously to the program scan, the second method works perfectly, even for momentary jog buttons. If the address is updated asynchronously, go with the first method.

Either way, you don't have to worry about some potential firmware problem from EZTouch, or what will happen if the comm cable gets cut in half.

Regards
Paul C.

marksji said:

I have to agree with icky on this one. Look for some communication problem somewhere. I use a lot of the EZ-TOUCH screens and the one thing they are notorious about is not liking electrical noise. When I've had momentary buttons that 'stick' it has always turned out to be bad communications between the EZ-T and the PLC.

Click to expand...

I have 2 PLCs and the touch screen all on the same network. Will I have a worry about communication hanging up with the 2 PLCs talking to each other, where the touch screen comunication getting hung?

Also failed to metion on the one PLC (AD 205) was installed year ago, and have not added in read / write to this plc yet, or the touch screen bits to this.

Plus there is alot of welding, plasma cutting ect due to the construction, but this probaly 50 feet or so away. So dont think we would have communication problems from that

BoxerBrats said:

I have 2 PLCs and the touch screen all on the same network. Will I have a worry about communication hanging up with the 2 PLCs talking to each other, where the touch screen comunication getting hung?

Click to expand...

Probably not; at least I haven't had that problem... Usually it seems that the EZ-T locks up, but that other devices on the network are unaffected.

BoxerBrats said:

Plus there is alot of welding, plasma cutting ect due to the construction, but this probaly 50 feet or so away. So dont think we would have communication problems from that

Click to expand...

Maybe, but maybe not... It depends on what circuit they're plugged into and if any of the grounds they're playing with (for welding) are in common with your PLC or EZ-T grounds. In short I think it's worth looking in to.

DirectNET and K-Sequence DO NOT support writing to Bits. If you have and address of BXXXX.X for one of your tags, you cannot use this to write with, e.i. a switch.

Tark said:

DirectNET and K-Sequence DO NOT support writing to Bits. If you have and address of BXXXX.X for one of your tags, you cannot use this to write with, e.i. a switch.

Click to expand...

i DONT QUITE UNDERSTAND...

WHEN i ADDRESSS THE INDICATOR BUTTON ON THE EZ-TOUCH I USE

START BUTTON 2-V4140/3
START INDICATOR LIGHT 2-V4141/3

ON DIRECTSOFT LADDER LOGIC I ADDRESS THESE INPUTS, AND OUTPUTS AS FOLLOWS

START BUTTON B4140.3
START INDICATOR LIGHT B4141.3


SHOLD i HAVE USED C-BITS INSTEAD LIKE THIS
EZ-TOUCH
START BUTTON 2-C100
START INDICATOR LIGHT 2-C101

DIRECSOFT LADDER LOGIC
START BUTTON C100
START INDICATOR LIGHT C101

Your second set of info is correct.

I've hit the "stuck button" problem before as well, and it I agree it is usually related to a communications hiccup. As a precaution on any critical item I put a timer in the ladder logic, and if the button is still on after one or two seconds I use the ladder logic to reset it. (Yes, I actually use the reset function for this!) That keeps a hung button from causing fits in the process.

As a precaution, I avoid maintained and alternate action pushbuttons in the screen. I use a momentary on the screen and do the rest in ladder logic. That way I am always in control.

And, if it is a really critical function, I use a hardwired switch to I/O instead of or in additon to the operator interface.

Tom Jenkins said:

As a precaution, I avoid maintained and alternate action pushbuttons in the screen. I use a momentary on the screen and do the rest in ladder logic. That way I am always in control.

Click to expand...

About 99% or momentary and all logic is done in ladder logic.

Another problem I saw yesterday, I have one section where there are 2 buttons (both are momentary) I use set / rst contacts to latch them in my probram. So basically button 1 latches, and button 2 unlatches... the problem is no matter which button I push it sends it to the same input.... I have checked both buttons have diffrent adddress, and everything looks right in my logic...

any clues, becausem my boss is warming up the chain saw, to correct this