Opta Analog expansion module RTD input not working

Official Hardware Opta
1

Hi all,

I'm having an issue using a Finder Opta Advanced with an A0602 Analog Expansion in Arduino PLC IDE.

My goal is simply to read a PT100 temperature sensor connected to the analog expansion.

Setup:

  • Finder Opta Advanced

  • A0602 Analog Expansion

  • Arduino PLC IDE 1.1.0

  • Arduino IDE 2.3.10

  • PLC Runtime 1.34.2

  • Opta and A0602 firmware updated to the latest versions

  • RS Components 4-wire PT100 (wired for 3-wire operation)

Problem:

If I configure I1 as Input - Voltage ADC, the PLC project compiles, downloads and runs normally.

If I change I1 to Input - RTD 2 wires or Input - RTD 3 wires, the project still compiles and downloads successfully, but the PLC immediately goes to SOURCE NOT OK / NOT RUNNING. This happens even with an otherwise empty project and no PLC code.

The Output window reports:

  • Booting PLC application... done.

  • Connected to ArduinoOpta_1p3

  • Target runtime version: 1.34.2

  • Target system info: 1.3.2 ArduinoOpta

However, as soon as RTD mode is selected, the application will not execute.

To verify the hardware, I uploaded the Arduino_Opta_Blueprint → Analog → RTD example in Arduino IDE. It works correctly and reads the PT100 (approximately 109.8 Ω at room temperature), so the sensor, wiring and analog expansion appear to be working correctly.

Has anyone successfully used a PT100 directly with the A0602 Analog Expansion in Arduino PLC IDE? Is there any additional configuration required for RTD inputs, or is this a known issue with PLC IDE?

Any suggestions would be appreciated.

2

Welcome

I do not have one of these but I will take a guess: All channels can measure 2-wire PT100 sensors. I would expect any project this involved would have an annotated schematic, please post it, following forum guidelines along with your code.

Only channels I1 and I2 support 3-wire PT100 connections, which provide better accuracy by compensating for lead resistance.

The PLC IDE automatically recognizes the expansion and exposes the PT100 I/O resources in the project once the hardware and firmware are configured correctly.

3

For now is focused not on code, but on hardware set up to get reading reading for I1.
Will say have issue with variable mapping between expansion input I1 and global variable due to lack of my kownlege.

4

Without we are just taking guesses which can take a lot of time and not solve your problem.

5

image
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6

Sorry but your fuzzy picture does not help. I do not have a board like that so without a schematic I have given you my best.

7

The picture shared in post #5 is functionally identical to the one included in the Opta user manual:

https://docs.arduino.cc/tutorials/opta-analog-exp/user-manual/#analog-rtd-input-mode

rtd-2wires-user
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📷

rtd-2wires-user.png by Arduino - CC BY-SA 4.0

8

Yes, identical of course. Problem is- that example from tutorial not working for me. With same setup i got PT100 (3 wire) reading on Arduino IDE. On PLC IDE not. Tryed on fast and slow task speeds, 3 wire, 2wire- same. Can be issue in RTD current? In Task speed? RTD reading is aroud 600ms and there no option to custom speed selection.

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Did i need any sketch in library here?
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9

Switched to wago cc100, back to this when have more time. On top on this with expansion opta won't run code automaticly after power cycle.Opta it's self wihtout expansion after power cycle run in auto.