Hi there. I'm an engineer on the Revolution Pi team. AMA.
Can these be programmed by any of the 61131-3 languages?
Revolution Pi – Industrial PC Based on Raspberry Pi
31–40 of 77 posts
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#32This would have been perfect for my last startup. Keeping those damn Pi's running when they were deployed across the country was a nightmare. The SD cards had around a 20% failure rate per year. Eventually I just started shipping each system with a backup SD card taped to the inside of the case.
I have a cluster at home, and that's about what I'm seeing. Good wall warts and good power cables reduces the chances of it happening, but doesn't bring it to zero.
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#33are my eyes mistaken, but a cardboard case? is that safe? fire hazard?
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#34Hi there. I'm an engineer on the Revolution Pi team. AMA.
When I first saw the product renders the box reminded me of some things packaged in cardboard. But actually that might not be such a bad idea for a Raspberry Pi type of computer in some applications. A lot can be done with printed cardboard for creating a fun case. A cardboard box version for the hobby developer targeting the 'pro' version could make development easier to get into.
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#35Hi there. I'm an engineer on the Revolution Pi team. AMA.
On the website, you mentioned that you run stock Raspbian with a real-time patch on the devices. I'm mostly curious about the real-time extensions you're using. Did you write the patch in-house? What real-time capabilities are supported on it? Is it just a better scheduler, or do you also include things like locking protocols? This isn't a particularly important question; I'm just a grad student in real-time research…
There's a patch set for the kernel called PREEMPT_RT:
https://wiki.linuxfoundation.org/realtime/start
It contains patches to get latencies down and touches numerous subsystems of the kernel. Most importantly, interrupt handlers become preemptible. (Normally interrupts are executed in "atomic context", i.e. they cannot be preempted. This also means e.g. that you can't sleep in an interrupt handler because the timer interrupt is disregarded. With PREEMPT_RT_FULL, interrupts are executed in "process context", i.e. as normal kernel threads which can be interrupted.)
We use the kernel branch of the Foundation (which contains a ton of patches required for hardware support of the Raspberry Pi), cherry-pick the realtime patch set on top, then apply three custom patches, one is a fix to make the USB driver's interrupt handler preemptible. The result is this branch:
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#36are my eyes mistaken, but a cardboard case? is that safe? fire hazard?
From the datasheet (linked on the website):
Housing type: DIN rail housing (for DIN rail version EN 50022) Housing material: Polycarbonate
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#37Hi there. I'm an engineer on the Revolution Pi team. AMA.
Can these be programmed by any of the 61131-3 languages?
Yes, with appropriate software. logi.CAD (an IEC 61131-3 automation platform) is pre-installed as a demo version and license keys are available at the online shop for a few bucks.
But noone is forcing you to use a specific software. You can use Python or even Bash. The input and output values are stored in a process image by an open source kernel driver (piControl) and you can access the process image through a char device. Just seek() to the value you're interested in and issue a read() or write().
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#38Hi there. I'm an engineer on the Revolution Pi team. AMA.
When I first saw the product renders the box reminded me of some things packaged in cardboard. But actually that might not be such a bad idea for a Raspberry Pi type of computer in some applications. A lot can be done with printed cardboard for creating a fun case. A cardboard box version for the hobby developer targeting the 'pro' version could make development easier to get into.
The case is made of polycarbonate. Cardboard would be interesting from an environmental perspective, but likely wouldn't be able to withstand the harsh conditions prescribed by EN 61131-2 (low/high temperatures, damp air, vibrations/shock etc). We add a safety margin to those conditions, e.g. 61131-2 requires safe operation at 55 degrees Celsius, we test at 60 degrees. The products are used e.g. in automotive applications where these harsh conditions are not just theoretical.
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#39This would have been perfect for my last startup. Keeping those damn Pi's running when they were deployed across the country was a nightmare. The SD cards had around a 20% failure rate per year. Eventually I just started shipping each system with a backup SD card taped to the inside of the case.
At work the SD cards lasted for about 1,5 year and then gave up.
I now disabled Ext4 journaling and am considering using the F2FS filesystem which is designed for flash storage.
Re: Revolution Pi – Industrial PC Based on Raspberry Pi
#40How industrial are we talking? Is it certified for use in industrial environments? I saw a few mentions of IEC61131-2, but I couldn't find whether it actually has certifications. If it is suitable for use in the industry, I can't wait to ditch ladder and Structured Text in favour of modern programming languages for industrial controllers.
They seem pretty solid in terms of their specs and certifications, but for industrial equipment I'm always worried about availability and vendor support. Can I get them shipped to a customer anywhere in the world on short notice? Will my vendor's engineers come to the plant with me to solve an inscrutable issue that has brought a machine down? Those answers are "yes" for the systems I'd be replacing, and almost certainly "no" for this thing, however cool it may be.