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Hello, support staff

Thank you for your help.
In the system of UMAC Turbo, there is a question about communication abnormality of ACC72E.

The LED (D2) of the ACC72E board goes out.
The LED of the ACC24E2A board turns off.

※Additional Information
ACC72E is a slave setting.
It is connected to the PLC master unit (Mitsubishi), and the NS LED of the master unit blinks.

D1-B: On
D1-C: On


Looking at the manual, the LED status of ACC72E is unknown abnormality, breakdown, occurrence of power failure
That is the cause.
Confirmation of power supply and cable length and terminating resistance has already been performed.

At the same time I found the next problem.
All the LEDs on the ACC24E2A board were off. (PWR, ENC 1, 2 AENA 1, 2 etc)

If there is a problem with the ACC72E hardware, will the watchdog relay trip?
Also, even if there is a problem with the board other than ACC72E, the watchdog relay trip
Is there a possibility of occurrence?

There is no information from the work site as to whether the watchdog relay is triping.

Please tell me if you have knowledge of past cases and countermeasures against these problems.

that's all, thank you very much.
This sounds like a hardware problem with the ACC-72E card. Any failure of this card would not typically cause a PMAC WD unless the failure interferes with the +5V DC power of the UMAC or causes serious DPRAM issues that would interfere with PMAC’s low level communication.

If all LEDs are off on the ACC-24E2A this may indicate the card is not getting power.

Contact the TSG group at with more details on the installed hardware.