DC link voltage too low warning

Amelie

Hello to everyone. I have 2 ABB Robots in my hand.

MODEL IRB 6700

CONTROLLER IRC 5.

Both Robots are fed on the same power line.

Suddenly, both robots started giving DC link voltage too low warning.

Error Code 34401

When I measure the energy coming to the robots, the problem does not appear.

I turned off the main power and checked the Cables by hand, there was no slack.

Robots have different failure times, so I don't think it's a sudden energy surge.

And I don't think it's a cable problem either. Because this problem started suddenly, both robots could not have their cables loose at the same time.

The description of the fault is written like this in the technical manual.

34401, DC link voltage too low warning

Description

In drive module arg, the drive unit at unit position arg has a DC

link voltage that is close to minimum limit.

Consequences

Operation will be possible but the system is close to a stopping

error.

Probable causes

The incoming mains voltage to the rectifier unit is out of

specification.

Recommended actions

1) Check for other hardware eventlog messages regarding

mains voltage problem.

2) Check incoming mains voltage. Change the mains tolerance

min so that the mains voltage is inside the specified interval.

3) Check that the correct voltage is selected with jumpers on

the transformer (optional).

4) Check all internal 3-phase components (main switch, mains

filter, fuse, contactors) and cabling in the drive module.

I tried all the possibilities but couldn't fix the problem.

I am sharing a photo of the fault below.

What are your suggestions for a solution?

If the main drive is out of order, can I replace it with the spare part I have?

What should I pay attention to when changing?

There is a warning on the main drive.

"Before replacing main drive system, remove any temp sensors adjacent to the heat sink."

What are the sensors listed here?

Since we have very intensive machines, I have no chance to make mistakes, what are the risks.

Could software problems occur?

Could there be a calibration problem in axes?

The labels of the spare parts are like this.

Is it a problem if I replace it?

There is a warning on the main drive.

"Before replacing main drive system, remove any temp sensors adjacent to the heat sink."

What are the sensors listed here?

What are your solutions and experiences? Please share with me.

Thanks everyone.

Amelie

Errors

graemepaulin

The warning only applies if you have the option temperature sensor fans - which alters the fan speed depending on the heat sink temperature.
The manual says you can remove the drive without issue - then you will be able to see the temperature sensors if they are fitted - see below.

you need to remove the sensors before fitting the drive.

The spare part you have is an earlier revision (07) than the part in the controller (rev12), but they will both do the job.

Amelie

Thank you for your answer. What else could be causing this malfunction?

graemepaulin

Looking at the error logs both robots are going down at approximately the same time so the issue would likely be on the incoming mains - has equipment recently been installed on the same incoming mains connection?

Amelie

No

Amelie

I measured the voltages, for 4 hours with a calibrated fluke multimeter and the results are as follows.

L1 : 211.6 V.
L2 : 213.1 V.
L3 : 213.4 V.
L1-L2 : 370.4
L1-L3 : 375.3 V
L2-L3 : 367.5 

What should i do if the values ​​are low? So how can I increase the voltage from the incoming mains

graemepaulin

This is low but the default tolerance of the Mains Tolerance Min parameter is 15% so it would not error on these values - but you are having intermittent errors so the voltage is probably sagging below the default 340 V (line to line) limit.

To keep the system going you can change the the Mains Tolerance Min parameter (in the Motion config file) from -0.15 to say -0.2 (-20% of nominal). The maximum is -1 (which is -100%).
This will affect the maximum speed of the robot.

It is probably something you will have to take up with your electricity supplier to sort out why the voltage is sagging so low.

Amelie

thanks for everything.