Why not put a touchscreen LCD on the CPU ?

danw

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Oct 2004
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midwest, USA
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Opto 22's EPIC
Opto-22-EPIC-sm.jpg
 
Nice, but I suspect the trend will be toward connecting the touchscreen every man woman and child carries in their pocket to the control system wirelessly.

Having it right on the PLC could be useful as long as you are authorized to open the enclosure to see and touch it.
 
That's lovely until condensation causes a screen press and gives the controller an unintentional command. Maybe there's a programmatic disable interlocked with the door ?

I can see this being clever or useful on 24V-only cabinets where the controller is visible through the door, or if the screen is easily decoupled and mounted in a cutout.

What's most likely is having a nice QR code sticker on the door of the control panel and a WiFi or Bluetooth access mechanism. You walk up and scan the QR with your HMI app, and it connects to the machine and brings up the appropriate screens. Get out of range and it won't work.
 
Why not put a touchscreen LCD on the CPU ?
One word... arcflash. Yes I get it, it's likely meant for cabinets that are solely 24v, but where do these really exist? Perhaps in some niche industries I suppose, and at tradeshows.

Years ago I would have bought into the cool factor of this gimmick, but nowadays I think the only value of an OI integrated into a CPU is for initial setup: setting comms, IP, etc.
 
One word... arcflash. Yes I get it, it's likely meant for cabinets that are solely 24v, but where do these really exist?

Worked on one CompactLogix that was in a split cabinet and 24v on the left side and 120 and up on the right side, it would work for that but.... thats still a lot work work programming the HMI/screen for the maintenance department because I would not want anyone else inside the cabinet

How about if it was a door mount and the screen was on the outside of the door? but still I dont see the upside being worth the potential downside.
 
There's an HDMI port too and USB inputs... Opto are working on touch drivers at the minute.

I have a Groov on my R&D bench at the minute. Can run Ignition Edge within the controller.
 
Most of the PLC's I know are locked inside a steel cabinet.
Yes, it would be way cool . . . but it could easily be years
between the times anyone needs to access it.

Of course, if the cost of the touch interface is low enough, and
it is rugged enough . . . Might be worth having.
Poet.
 
OK, so I was too quick to judge... and did not have a lot of time yesterday also after the_msp's comment on the HDMI port got me thinking, I watched some of the video below and I have to say I am impressed and will be buying one.

I remember a cabinet builder on this site made a double hinge on the HMI, that way it could be swung inward and the tech could be working on the PLC (watching I/O) and still see and operate the HMI without having to step back, close the door and try to watch the HMI with one eye and watch PLC/Drive/Relay/whatever with the other, but with this PLC you can see the HMI and have the second screen on the cabinet connected with the HDMI cable.

8:50 in the video is where they talk about the screen

https://info.opto22.com/this-is-epic-introducing-groov-epic

Specs and wiring diagrams are in the HMI also and its programmed with Codesys
 
I could see it being semi-useful for monitoring state of digital IO or analogue values, as an actual touchscreen for control - seems a bit of a daft idea.
 
I would prefer to have more ethernet ports on PLC and if you need small HMI
interface have it mounted in cabinet cutout. Additional Ethernet ports allow you to
connect HMI directly to PLC and still have Ethernet comms available for networking.
This would be helpful on small applications where a switch would not be necessary.
 
Red Lion also has the HMI with I/O which makes it nice for interfacing
the controls around the HMI but I personally don't like all my I/O on the
HMI for wiring purposes to the remaining devices.

Agree. We use the Horner XL7's a lot, but usually have the cabinet controls come into the built-in I/O, and use remote I/O for everything else.... Unless it's a real small machine. We also use some of the networked drive I/O where it's convenient :)
 
How many people keep the cabinet door open so you can see the PLC?

I do a lot when commissioning a machine or troubleshooting, most of the time the last thing I do when commissioning is to install the cabinet doors.

Once you get to know a machine like its part of you or your family, you dont need a laptop you can just look at the LED's on the I/O's and knowing what the machine should be doing (or not) 99% of the time you can just put the machine in manual and tell whats not working, most of the failures are input switches, after so many machine cycles they are bound to fail or move out of adjustment.

This was before arc flash was a big deal... I now its changing so I have been seeing more I/O list able to pull up on the HMI

OT: If the PLC program is written correctly and you have a HMI on the machine then you should not even have to ask 'what's wrong'... the programmer should be able to know what's not working and tell the tech/operator what is wrong on the HMI once its not, I do know depending on the complexity of the program its not always that simple, but its possible.
 

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