hardening Arduino IO for industrial use - Page 1
Forum section: electronics / general

author: snarkysparky
author_rank: Frequent Contributor
timestamp: January 18, 2019, 03:10:28 pm
content: I need to use an Arduino mega 2560 for a piece of lab equipment. But CPU IO is not hardened enough for running IOaround a machine I believe. So I need an interface board to buffer the IO.I don't want to build it myself, so does anyone know a source to buy this. Why is it not a commonly available thing.All it needs to be is some ULN2003 buffers on input and output with relays.And no i can't change to another platform. So sorry for the XY question.

author: paf
author_rank: Regular Contributor
timestamp: January 18, 2019, 03:27:44 pm
content: You can buy one rugged Arduino Mega from here:https://www.rugged-circuits.com/10-ways-to-destroy-an-arduino/

author: tsman
author_rank: Frequent Contributor
timestamp: January 18, 2019, 03:30:38 pm
content: There are several of them around. Search for "Arduino PLC shield" e.g.https://www.industrialshields.com/shop/category/ethernet-plc-1Won't be cheap though.Linked to the wrong one. The Ethernet models have a ATmega2560 inside. The 20 I/O ones have a ATmega32u4 inside.

author: Kalin
author_rank: Regular Contributor
timestamp: January 18, 2019, 07:19:03 pm
content: Quote from: tsman on January 18, 2019, 03:30:38 pmAs someone who uses PLC's in industrial regularly. Those are an order of magnitude cheaper than a real PLC.Sent from my SM-G965W using Tapatalk

author: coromonadalix
author_rank: Super Contributor
timestamp: January 19, 2019, 01:55:20 pm
content: I use some plc too, but i've seen some very well made arduino shields, with opto coupled inputs outputs, current llimited / input protection diodesThe given link :https://www.industrialshields.com/shop/category/20-i-os-plc-2Is a very good implementations, and multiple communication protocolsThis one too:https://www.controllino.biz/The paf memeber link is very good :https://www.rugged-circuits.com/products/it will give you the basicsThe plc shield seems very well tought and tested, you can stack two of themFinally the opened source project :http://www.openplcproject.com/Getting started :http://www.openplcproject.com/getting-started-arduinoAn engineer at my job told me this link, he's adding up this system to a filament mahine we use 24/24hOther open source infos and coding ? :https://www.open-electronics.org/arduino-as-a-programmable-logic-controller-plc/

author: Kalin
author_rank: Regular Contributor
timestamp: January 19, 2019, 04:09:45 pm
content: Quote from: coromonadalix on January 19, 2019, 01:55:20 pmI agree. I don't mean to disparage these products. Only to highlight the fact that there are savings to be had in the area. In many applications these are a good solution. Especially in machine building applications these are ideal. I wouldn't use them to run a production line but in a piece of equipment that will not be changed frequently I think they would be a great fit.Sent from my SM-G965W using Tapatalk

author: thieringpeti
author_rank: Contributor
timestamp: January 20, 2019, 09:39:16 am
content: Hi!I've extracted these boards from real production environment, both were part of a custom-made quality approval & test & firmware-uploading equipment. One of these was the control board of a pneumatically operated pogo-pin test fixture, and the other one was controlled some simple assembly stage, I think, a few pneumatic acutators.The common of these boards, that both of them are using ATMEGA128, which is capable of running Arduino-developed firmware, but these boards were put in operation around 2005-2008, when Arduino wasn't widely spread. One of the boards have an extra EEPROM, a 24C64WP connected to the ATMEGA. (I think, for the error log).One of the boards have only 8 relay outputs, and 8 relay inputs wired to the connectors, and the two UART's are simply level-translated by a MAX202. Note, the small G5V-1 relays can be easily interchanged, because all of them were mounted into a socket. The other board is a bit more complex, UART can be switched to RS485 or RS232 or USB (FT232). This board has a more sophisticated SMPS, and high-current automotive-grade open collector drivers VN340SP. In this board, inputs are only wired like zones in alarm system control panels. Note, that ADC's were multiplexed by two 4051's. Protection is zener-resistor voltage divider. The serial port is isolated by optocouplers (RxD, Txd, direction control), power is coupled by a Traco-Power TMA0505S module.So, Arduino-like devices can be used instead of PLC's, but with limitations: you MUST specify the source code for the end-user (.ino file AND all library dependencies, custom-made low level drivers, etc), if further modifications may be performed by others than You, and You must be responsible for the proper rugging, and reliability of the I/O's. Software isn't as big problem I think, as PLC promoters will say, because You can also make a bad software for a PLC, like for an MCU. The key is proper testing before put into the production line. PLC's have the advantage, that the code can be read back to the editor software, for later modification or for transferring into another PLC. (but if the author wants, can protect it with a password, like readout lock bit on the Atmega).If You want to design an industrial shield for your Arduino, the main points, which will help you in your project:- use relay outputs, if you have enough space, and no PWM is needed. Put the relays into sockets.- drive the relays with ULN2803 or some kind of good reliability transistors, or FET's. Automotive-grade open collector driver may be an overkill.- if you have enough space, use LED's everywhere. Design them on the board, some 0603 or 0805's. They are cheap, and help you while debugging.- use optocoupled inputs, if any of the input signal will came into the circuit more than a dozen of inches away, or from a different equipment, e.g. VFD's, remote sensors.- use LC or RC filters around VFD's at your inputs. You may experience nasty EMC issues around high power VFD drives! Beware of ground loops!Good luck!

author: thieringpeti
author_rank: Contributor
timestamp: January 20, 2019, 09:40:15 am
content: The other board with FTDI and automotive-grade open collectors.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 26, 2019, 10:13:43 am
content: I just bumped into:https://industruino.com/

author: coromonadalix
author_rank: Super Contributor
timestamp: January 27, 2019, 02:50:24 am
content: Quote from: Doctorandus_P on January 26, 2019, 10:13:43 amThanks never saw this one.