Custom ASCII serial over ethernet to AB PLC

[BachPhi]

No skin in this game, just an EV and embedded stuff enthusiast.

The most reliable non-PLC device I've got in my shop or boat is a FriendlyElec NanoPi NEO LTS, running Node-Red. I set it up to monitor some stuff aboard about five years ago and send me SMS notifications, and I haven't touched it since. Power outages, brownouts, lightning storms, a blown inverter... it just keeps going.

TTL serial port, Ethernet, Linux so Python and Node-Red (thus PyLogix and the Node-Red CIP Ethernet nodes), aluminum case, 70C working temperature. Twenty bucks.

Is this the right link for NanoPi NEO3-LTS ? https://www.friendlyelec.com/index.php?route=product/product&product_id=279

I see it now for NanoPi NEO-LTS: https://www.friendlyelec.com/index.php?route=product/product&product_id=132

 

[BachPhi]

All great options!

The PointIO modules are less expensive, making that more interesting at scale (over a hundred chargers expected on campus)

Dmroeder, I am going to dive into your project. I do have some temperature constraints in some areas. I expect temps to reach 140° F in some sites.

I have a call in to Redlion to see what they recommend.

I'll post my progress and share what I can. Thanks! :site:

I don't see how the pointIO modules are less expensive.

1734-232ASC is $330, plus AENTR, EP24VDC, labor cost of stripping & wiring, program & debugging time...
vs
RTA 435NBX $450/port Plug & Play.

 

[drbitboy]

Apparently you can run at least serial TTL ports off one ESP32; see below; repo is here.

And the .ino code to handle a UART Wifi server is not very long, see here.

Nerdrooling.

 

[Ken Roach]

But then you're dealing with MicroPython on the ESP32, and limited to WiFi, right ?

I think Dustin said that MicroPython and pyLogix work together, so the basics of getting data from a serial poll to the EVSE's to a ControlLogix are probably there.

My Python and MicroPython skills are rudimentary at best so I don't want to opine on the effort or labor involved.

25 years ago I was in the sawmill business and had a colleague named Boyd who preferred embedded custom hardware to anything we could do with a PLC. So much cheaper, right ? His career is littered with a trail of things that nobody else knows how they work.

Up in Kelowna, years after we'd done the startup together, I remember opening up a junction box and finding a custom printed circuit arrangement screwed onto chunk of particle board.

"Oh god", the electrician complained. "Another P.C. Boyd."

 

[Ken Roach]

Full disclosure: I had to impose a tiny bit of self-discipline to not order a NanoPi kit with enclosure and LCD display last night.

"You can have another toy when you finish the NMEA 0183 holding tank monitor, Kenneth."

 

[drbitboy]

Full disclosure: I had to impose a tiny bit of self-discipline to not order a NanoPi kit with enclosure and LCD display last night.

WiFi to serial bridge, with perhaps much of the code available on Github? You and me both

330$/1734-232ASC/1-port vs. ~30$/EPS32/3-TTL-ports, so $320 per port saved, plus wired RS-232 vs WiFi connections, times 19 units to start and 100 units potentially? And the update cadence is only 0.1Hz? That pays for a fair bit of development time.

And excuse my ignorance, but isn't driving 100, or even 19, 1734 modules with a single AB PLC problematic?

There could be a Modbus server with registers for monitoring and driving three chargers on each NanoPi. It might be a Boyd, but it's all bog standard tech that is accessible to multiple folks, if not everyone.

 

[L33er]

Haven't we learned anything? Boy rhymes with Boyd. I don't think we want to go down that road.
Each 1734-232ASC will consume 75ma, therefore will need a few of AENTR & EP24VDC.

And you cannot have too many TCP sockets to a single PLC either.

The Nanopi Neo LTS that comes with the case looks neat and all , but to access the serial pins, the case needs to be removed and convert the TTL to serial rs-232 with PSU-ONECOM.

Perhaps the best solution is to use a few of these 16 ports to a PC and then on to the PLC.

 

[drbitboy]

Haven't we learned anything? Boy rhymes with Boyd. I don't think we want to go down that road.

LOL. I am not going to argue on a relative scale, but on an absolute scale every solution here is going to have some of that, no?

The Nanopi Neo LTS that comes with the case looks neat and all , but to access the serial pins, the case needs to be removed and convert the TTL to serial rs-232 with PSU-ONECOM.

Perhaps the best solution is to use a few of these 16 ports to a PC and then on to the PLC.

OP said the charger serial are TTL already, so it's the other way 'round i.e. wiring from a NanoPi to the charger is going to be easier than wiring to that 16-port serial, and the WiFi is a huge win over USB cables. Although TTL may require one NanoPi per charger instead of three, depending on the distances between chargers. And the TCP port limitation on the PLC can be solved other ways.

But we are agreed a the -232ASC is not going to be a good solution?