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Industrial application w/ Touch

Posted: Wed Oct 28, 2015 5:19 pm
by BAStumm
Have been using RPi in the products my company builds for some time now and anxiously awaited the arrival of the RPi official touchscreen. Now that it is available I've started to question if it is suitable for industrial applications.

In my application the screen would need to be mounted away from the RPi by about 2 meters (80 inches) of cabling. In addition, there is high voltage power (up to 277VAC) present in the machines we build along with noisy devices such as step motor drivers (24VDC) and zero cross fired SSR's (110~277VAC 50/60Hz) for a resistive heating lamp application. Granted, noisy or high voltage wires can be routed so they do not come close to the flex cable used by the RPi touchscreen.

Am I doomed for failure? Am I overly concerned over nothing? Is it possible to get shielded cabling for the screen? Some sort of adapter to change from flex to shielded ribbon cable and back at the other end? Other ideas?

Re: Industrial application w/ Touch

Posted: Wed Oct 28, 2015 5:43 pm
by rpdom
BAStumm wrote:Is it possible to get shielded cabling for the screen? Some sort of adapter to change from flex to shielded ribbon cable and back at the other end? Other ideas?
Some people have mentioned using a pair of adaptors that connect a ribbon cable at each end to a standard HDMI socket, so you can use an HDMI cable to extend the connection. That cable will be shielded against interference. Not that it does NOT convert any signals to an HDMI compatible format, it just enables you to use the cables.

Re: Industrial application w/ Touch

Posted: Wed Oct 28, 2015 5:58 pm
by BAStumm
Any idea where one buys this HDMI adapter? I did find something for the CSI port (should work for DSI?) that converts from flex to ribbon cable with IDC connectors which would allow me to use shielded round ribbon cable. http://www.bitwizard.nl/shop/raspberry- ... -extension

Re: Industrial application w/ Touch

Posted: Wed Oct 28, 2015 6:34 pm
by mikronauts
Use two Pi's, networked.
BAStumm wrote:Have been using RPi in the products my company builds for some time now and anxiously awaited the arrival of the RPi official touchscreen. Now that it is available I've started to question if it is suitable for industrial applications.

In my application the screen would need to be mounted away from the RPi by about 2 meters (80 inches) of cabling. In addition, there is high voltage power (up to 277VAC) present in the machines we build along with noisy devices such as step motor drivers (24VDC) and zero cross fired SSR's (110~277VAC 50/60Hz) for a resistive heating lamp application. Granted, noisy or high voltage wires can be routed so they do not come close to the flex cable used by the RPi touchscreen.

Am I doomed for failure? Am I overly concerned over nothing? Is it possible to get shielded cabling for the screen? Some sort of adapter to change from flex to shielded ribbon cable and back at the other end? Other ideas?

Re: Industrial application w/ Touch

Posted: Wed Oct 28, 2015 6:35 pm
by rpdom
I believe the CSI and DSI interfaces use the same number of pins, but I'm not sure if the data pairs match up according to the early B schematics the data pairs use the same pins.

If they do, then something like https://www.tindie.com/products/freto/p ... extension/ should do the job.

Re: Industrial application w/ Touch

Posted: Wed Oct 28, 2015 6:47 pm
by BAStumm
Thank you, I think I will try this option using the HDMI cable + adapter boards. I will report back my findings.
rpdom wrote:I believe the CSI and DSI interfaces use the same number of pins, but I'm not sure if the data pairs match up according to the early B schematics the data pairs use the same pins.

If they do, then something like https://www.tindie.com/products/freto/p ... extension/ should do the job.

Re: Industrial application w/ Touch

Posted: Wed Oct 28, 2015 9:20 pm
by gadgetoid
I've used that adaptor ( we sell it at Pimoroni ) and it appears to work fine. I only tested it with whatever HDMI cable I had to hand, though, so as always YMMV!

Re: Industrial application w/ Touch

Posted: Wed Oct 28, 2015 9:24 pm
by BAStumm
gadgetoid wrote:I've used that adaptor ( we sell it at Pimoroni ) and it appears to work fine. I only tested it with whatever HDMI cable I had to hand, though, so as always YMMV!
Used with RPi display or camera? I'm hoping for good mileage when used for official RPi display...

Re: Industrial application w/ Touch

Posted: Thu Oct 29, 2015 12:16 am
by gadgetoid
The RPi display. In retrospect, it shouldn't really be surprising that it works although I did wonder if the camera might have used fewer signal lines and thus resulted in an adapter which didn't support the display. Apparently not, though, it works perfectly.

I've not tested it for any significant amount of time since the real difficulty was taming the HDMI cable enough to stop it sheering the ribbon cables off, which generally involved me having 4 hands.

Re: Industrial application w/ Touch

Posted: Fri Oct 30, 2015 11:43 am
by 6by9
If you check the schematics, the camera actually uses 2 EXTRA GPIOs over the display - they control powering the sensor up, and the LED on the camera board (it was meant to be a clock source originally, but that caused EMC issues).
The camera does get power down there too, but that's only 3.3V and the display wants 5V so you'll have to sort something else for that.

Re: Industrial application w/ Touch

Posted: Mon Nov 02, 2015 4:39 pm
by Dave31836
Before committing to an industrial application, I would advise thoroughly testing by power cycling the system several hundred times to see if it consistently comes up running. My own tests have failed on three systems and am waiting for an update to either the hw or sw.

Re: Industrial application w/ Touch

Posted: Mon Nov 02, 2015 4:45 pm
by BAStumm
Do you refer to the display or are you referring to RPi OS (SD Card) becoming corrupted? My application includes battery backup with safe shutdown on power loss. If you refer to the screen then would you mind linking me to the thread discussing the issue?

On a side note, can anyone confirm the input voltage range of the display? I thought I read somewhere that it could take in 5 to 12VDC but the display board that fixes to the back of the screen just says 5V. I can't seem to find the reference to 12v anymore, not sure where I saw it.

Re: Industrial application w/ Touch

Posted: Mon Nov 02, 2015 5:03 pm
by JimmyN
BAStumm wrote: On a side note, can anyone confirm the input voltage range of the display? I thought I read somewhere that it could take in 5 to 12VDC but the display board that fixes to the back of the screen just says 5V. I can't seem to find the reference to 12v anymore, not sure where I saw it.
5 volt MAX, you can use the same power source as the RPi. I put it on a lab bench power supply and I turned the voltage all the way down to 3.3V and it still worked, and was drawing about 455mA IIRC, but don't go any higher than 5V.

Re: Industrial application w/ Touch

Posted: Tue Nov 03, 2015 10:54 am
by Dave31836
BAStumm wrote:Do you refer to the display or are you referring to RPi OS (SD Card) becoming corrupted? My application includes battery backup with safe shutdown on power loss. If you refer to the screen then would you mind linking me to the thread discussing the issue?

On a side note, can anyone confirm the input voltage range of the display? I thought I read somewhere that it could take in 5 to 12VDC but the display board that fixes to the back of the screen just says 5V. I can't seem to find the reference to 12v anymore, not sure where I saw it.
My three systems consistently boot successfully off the sd card.... The display fails a few percent of reboots and the touch fails more frequently.... All of my boots are controlled.... Sudo reboot, eg.

Re: Industrial application w/ Touch

Posted: Tue Nov 03, 2015 10:56 am
by Dave31836
Dave31836 wrote:
BAStumm wrote:Do you refer to the display or are you referring to RPi OS (SD Card) becoming corrupted? My application includes battery backup with safe shutdown on power loss. If you refer to the screen then would you mind linking me to the thread discussing the issue?

On a side note, can anyone confirm the input voltage range of the display? I thought I read somewhere that it could take in 5 to 12VDC but the display board that fixes to the back of the screen just says 5V. I can't seem to find the reference to 12v anymore, not sure where I saw it.
My three systems consistently boot successfully off the sd card.... The display fails a few percent of reboots and the touch fails more frequently.... All of my boots are controlled.... Sudo reboot, eg.
Refer to topic called 'Displat testing'