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I need a device to read multiple Analog Inputs, and write 2 analog outputs

SensoredHacker0 — Fri, 01 May 2026 13:20:49 GMT

Hello All,
My Parent Company has been using Opto22 Groov Rios for expanding Analog IO to PLC systems.
The issue we have with these devices is that the IO periodically freezes, maintaining the analog outputs.
We make compression based hot water heaters, and this behaviour causes some undesired effects.

The red box is indicating that the Analog sensors have stopped updating.

Anyway, we are searching for a suitable replacement. The devices operate in a control panel,
an may be subject to electrical noise, and heat from -10F to 120F
we would really like something with at least 10 Analog inputs.

Modbus is fine. We have some experience writing other protocols, but that is frequently tedious in

A PLC programing environment. We need a professional device, with a Din mounted case, no bare circuit boards.
Analog outputs 0-10V output would be great.

The groov Rios do what we want, the specs match our needs. Its their failure conditions that we have a problem with. We have brought this up with
Opto22, and no solution has been presented. Its a thing that happens. No one knows why, or has a fix. its been about a
year of dealing with this, and I'm so over it.

If there are alternatives, I would love to hear about them.

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

SensoredHacker0 — Tue, 05 May 2026 19:27:11 GMT

exactly. I mean the rios look fine. its this one weird bug effecting standard operations. I think at the time we went with them was in the chip shortage, and couldn't get anything else. maybe that was a clue!
Anyway, lots of things look good on paper. Talking with folks lets you know what is legit.

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

shabaz — Mon, 04 May 2026 20:03:51 GMT

I just remembered that BeagleBone people used the MSPM0 in I2C peripheral mode too (they call it I2C target mode for some reason). They used it to make the MSPM0 replace an I2C EEPROM and I2C ADC, they copied the register detail from real EEPROM/ADC chips. I'm hoping this code can provide a start: mspm0-adc-eeprom/source/modules at main · beagleboard/mspm0-adc-eeprom

Actually, just thinking, if there's enough Flash space then the entire project could be used as-is, and append the extra code. That way a single device could be a multi-purpose EEPROM, ADC and UART bridge (I wouldn't be using the EEROM/ADC though).

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

Jan Cumps — Mon, 04 May 2026 19:35:22 GMT

Someone wrote a bitbang implementation for Pico PIO: https://github.com/thomasfla/pico-pio-uart-dma-rs485

I didn't read the code yet. I'm gathering resources.

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

shabaz — Mon, 04 May 2026 18:49:59 GMT

I've been considering that part (SC16IS740), I might go with it,. I suspect the SD16IS740 is also possibly a pre-programmed microcontroller. I thought DIY with an MSPM0 might be straightforward because the behavior of the SD16IS740 part is well-documented because it is in turn based on a historical part which had a parallel bus.

If I went the DIY route, then maybe to save time coding, I initially wouldn't bother with all the registers, I'd hard-code it to perhaps 9600 baud, and hard-code the RTS behavior all ready for attaching the RS-485 transceiver. I'd also not need a crystal oscillator, since the MSPM0 part doesn't use that. What was attractive is that I could use the MSPM0 parts for something else if it turns out less RS-485 interfaces are needed. Disadvantage is that it's another device to develop for and program! I'd only consider it if I can fairly quicky get it to work.

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

Jan Cumps — Mon, 04 May 2026 17:38:05 GMT

[quote userid="123345" url="~/technologies/industrial-automation-space/f/forum/56902/i-need-a-device-to-read-multiple-analog-inputs-and-write-2-analog-outputs/235296"] I've been considering creating the opposite end, a device to read in the measurements (guessing Modbus RTU?) and acting as an I2C slave.... So I'm curious to make a sort of RS485 to I2C bridge. Such parts do exist but are pricey.[/quote]

This NXP IC has RS485 to SPI / i2c parts: SC16IS7x0

I have an AVNET Pi-based device here that uses the SC16IS740. It has 2 pins to change i2c address.

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

shabaz — Sun, 03 May 2026 15:00:12 GMT

Hi Michael, it would be great to have per-port isolation, but a sort of compromise idea was to put one data acquisition module per RS485 interface and just accept that just one or a few ports would be used per module (each bridge interface having isolation, even if the module does or doesn't). It would be straightforward to add more RS485 interfaces to the "hub" processor if the bridge circuit had selectable I2C addressing. I don't mind too much if that is limited in practise to say 4-8 RS-485 interfaces, since another hub could be added (trying to keep this all low-cost but at the same time with some element of graceful degrading if one hub ever fails); it's for my brother's business (heating/air-con related; some of those RS-485 interfaces in future will go to other equipment, not data acquisition modules).

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

michaelkellett — Sun, 03 May 2026 14:32:30 GMT

Would you go for isolation between the analogue ports or only between the block of analogue ports and the RS485 ?

I think that your data recorder (I think you Road Tested one) is fully isolated , but that many industrial IO blocks only isolate in blocks (or not at all).

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

shabaz — Sun, 03 May 2026 14:18:18 GMT

I'd be interested : ) I've been considering creating the opposite end, a device to read in the measurements (guessing Modbus RTU?) and acting as an I2C slave.. for a couple of boring reasons, primarily I didn't have many free pins on my microcontroller. So I'm curious to make a sort of RS485 to I2C bridge. Such parts do exist but are pricey. Was thinking of using the good old MSPM0 chip since it's cheap and we know how to use it very effectively since we did all those experiments on it last year!

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

Jan Cumps — Sun, 03 May 2026 13:48:29 GMT

I may try to make something like this. 24 volt based, RS485 comms, The usual industrial voltage and current source / sinks. Decent isolation / protection and DIN housing.

I have devices with RS485 and industrial IO that I could use to test it with.

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

Jan Cumps — Sun, 03 May 2026 08:52:38 GMT

Overdigit has analogue I/O with modbus, din mounted.

4 chan analogue i/o configurable, 10 V: EX04AIO

4 channels can be I and O at the same time. They have pins for both, and both can be controlled via ModBus at the same time.

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

phoenixcomm — Sun, 03 May 2026 06:09:30 GMT

Question how many inputs do you need (a) what is there Amplitude Vmax(b) what frequency do you want to get the info (c)

how many devices (quantity) do you need and would you get dirty and DIY Them? Y/N

if you are audio range there a bunch of D mux chips

and one more thing would you be willing to do CAN in the Box...that is to say between your box and the sensor... but then the sensor has to talk CAN but if the sensors are stupid then you could put a micro-embeded cpu at the far end. TI has a broad range of these beasts as they are use in automotive industry

btw one more you could use Semiconductor Analog Mux .~~ Cris H

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

geralds — Fri, 01 May 2026 13:53:45 GMT

Hi SensoredHacker0

You can use Eaton Easy E4 for example:

https://at.farnell.com/en-AT/c/automation-process-control/process-controllers-programmers-indicators?st=eaton+easy+E4

1) The controller (with display, just one of 3 possible modules; DC, UC, AC versions):

https://at.farnell.com/en-AT/eaton-moeller/easy-e4-dc-12tc1/control-relay-w-display-24vdc/dp/3371899

4 analogue inputs, 8 digital inputs, 4 digital outputs

2) Analog expansion module:

https://at.farnell.com/en-AT/eaton-moeller/easy-e4-dc-6ae1/analog-input-output-module-4-i/dp/3371908

4 analogue inputs, 2 analogue outputs

Here you need 2 modules

3) If you want reading temp. sensors:

https://at.farnell.com/en-AT/eaton-moeller/easy-e4-dc-4pe1/analog-input-module-4-i-p-24vdc/dp/3371912?MER=BR-MER-PDP-RECO-STM72194

4 analogue inputs, 2 or 3 wired PTxxxx

At Farnell, you can find some other modules you want to combine together.

Best Regards
Gerald

RE: I need a device to read multiple Analog Inputs, and write 2 analog outputs

michaelkellett — Fri, 01 May 2026 13:39:16 GMT

I didn't even Google - merely Duck, Duck went and found loads. (Google would find more but I don't use it if I don't have to)

These look not bad:

https://www.lucid-control.com/lucid485-serial-rs-485-analog-digital-io-module-modbus-rtu/

I've designed such things in the past - and would be happy to do so again (commercially) but it wouldn't be worthwhile unless you use a lot of them.

RE: Interfacing EVAL-AD5700 with Microcontroller & Transmitter

meera_hussien — Thu, 23 Apr 2026 03:56:00 GMT

Thanks for the update fonhuaicho . I will relook into this and see if i can get this working. I would also like to inform that I have tried to look for some reference on the wiring or the setup but didn't find any. If you know any site or resources that is related to my setup, please do share it.

Appreciate your help.

Thank you.

Interfacing EVAL-AD5700 with Microcontroller & Transmitter

meera_hussien — Thu, 10 Jul 2025 02:04:19 GMT

Hi,

I am trying to interface the EVAL-AD5700 with STM or Arduino Microcontroller and also Yokogawa Transmitter. Has anyone ever tried this configuration or has experience using the HART modem.

and the current setup is as follow

RE: Interfacing EVAL-AD5700 with Microcontroller & Transmitter

fonhuaicho — Wed, 15 Apr 2026 10:57:15 GMT

Nice setup 👍

People have interfaced the AD5700 with STM/Arduino over SPI without much issue. Just make sure the HART signal is properly coupled onto the 4-20 mA loop using the correct resistor and capacitor network.

The “HART in/out” labeling can be confusing, it’s basically the same loop signal.

RE: Interfacing EVAL-AD5700 with Microcontroller & Transmitter

meera_hussien — Fri, 21 Nov 2025 03:31:18 GMT

Thanks mp2100 . And sorry for my late response. I have asked for help from the official analog devices forum. So far no answer yet.

RE: Interfacing EVAL-AD5700 with Microcontroller & Transmitter

mp2100 — Mon, 28 Jul 2025 01:20:12 GMT

Interesting.. I hadm’t seen this EVAL board.. I will have to read up on it.

I’m wondering why the terminals say HART in and HART out. HART is a 1200 bps serial comm imposed on the 4-20 mA signal. It’s not in and out.

Allen

RE: 4-20mA Input To Microcontroller

meera_hussien — Tue, 28 May 2024 08:35:43 GMT

Thanks robogary .

4-20mA Input To Microcontroller

meera_hussien — Fri, 24 May 2024 07:36:02 GMT

What is the best practice to create a 4-20mA input that can be feed in to microcontroller ADC pin?

RE: 4-20mA Input To Microcontroller

meera_hussien — Tue, 28 May 2024 08:34:26 GMT

Thanks for the info Steve524

RE: 4-20mA Input To Microcontroller

meera_hussien — Tue, 28 May 2024 08:33:00 GMT

Thanks for the info michaelkellett . I will look into the details.

Ultrasonic signal generator

CKDAF — Mon, 27 May 2024 00:33:49 GMT

I am currently using Olympus 5077PR square wave emitter/receiver for ultrasound signal generator. I am wondering if this could be replaced with GW INSTEK SFG-1003 from your shop?

RE: Ultrasonic signal generator

michaelkellett — Mon, 27 May 2024 08:03:17 GMT

E14 is an engineering forum and only indirectly related to Farnell, Newark and Avnet - so for specific advice about products sold by the various outlets you should ask them directly.

SO this advice is based on my engineering experience and I don't represent any one but me.

I have designed piezo electric transducers of various types.

The Olympus generator is specifically designed for driving piezo transducers and picking up return signals.

The GW INSTEK SFG-1003 is a low cost signal generator.

The 5077 can generate 400V pulses, the 1003 can manage 10V on a high impedance load.

They are not equivalent.

If you were to explain what sort of device you wish to drive and the kind of experiments that you want to do it might be possible to give you more useful advice.