Hi,

running the attached flowfor reading digital inputs, after some time flow throws continuously error Messages:

"DIx: Invalid digital Input value."

The error persists until re-deploying the flow or re-starting.

Are there ideas about possible causes?

Thanks in advance.

Hi,

looks like a hardware error.

I make this test flow an run it over night.

Tomorrow I write if any errors occurs.

Ocean_

Hi again,

I have look on my flow and there are not any errors.

Please check following steps.

1. Remove I/O shield from IOT2000 and restart flow.

2. Check jumper on IOT2000 mainboard.

3. Make a fresh image and test flow again.

4. Look in /var/volatile/log in file messages for mraa messages (you can use WinSCP program).

Ocean_.

Thank you for the  investigation and the information!

I figured out, that cause of the behavior seems to be some kind of behavioral coupling between this flow and another flow running in parallel, reading PLC variables from a connected S7-1200 using the communication nodes from node-red-contrib-s7.

When the S7-communication is deactivated, digital input access is stable down to cycle time of about 100 milliseconds. After activating S7 communication with actualization rate of 1 second, and reading 9 variables from a DB, accessing digital input values stops after some time, even with slower cycle time of 500 ms.

Hi,

its very suspect because the I/O shield works with mraa and S7 with sockets.

Can you update node-red and test again ?:

npm -g update node-red

Ocean_

Hi,

I did this already before: the target runs NodeRed v0.18.1.

Best Regards