Does EtherCAT Module Status LED ever turn green?


I am using the AnyBus EtherCAT module. I have seen the Module Status LED light red, but I have never seen it light green. Under what condition will it light green?




You will want to reach out to the OEM of the device for trouble shooting. But here is the user guide for the Anybus S Ethercat manual, Page 10 describes the LED’s.



Sorry for not being clearer. I am using CompactCOM B40 device.
As far as I know - HMS is the OEM.




OEM might not be the best description. You would want to talk to the company that integrated the M40 into their product/device. We provide the hardware and the programming interface for the Compactcom but they write a host application for the device. You can find the implementation guides we provide here. Here is how we have the LED’s configured for our starter application. Since you have a B40 and a Module LED I am not sure what that will be doing.


I am the one that integrated the MB40. I interfaced to the example code and have a working EtherCAT device. I am just wondering if/when the 4 dual-colored LEDs that are defined here

light the “other” colors. Perhaps you can point me to the specific functions where the LEDs are currently lit and I can look at adding more functionality.



Hi @jmcdevitt ,

Thanks this helps me understand your question.

There isn’t a straight forward answer to this. Depending on how you have built your hardware will change how these LED’s are Set. For most applications you would not be controlling the LED’s yourself and the compactcom is going to be controlling the LED based off of it’s state. The host application you write does not need to manage this, you would only want to set the status of the module

Do you have more then the 2 standard LED’s for Ethercat? To pass EtherCat conformance they require the LED’s to act as shown above. You might fail conformance if you change the LED states.

You might be able to turn them on and off by controlling the GPIO pins they are connected to, as mentioned above this depends on how you have the hardware configured.



I have the 4 LEDs as suggested in the Design Guide. Do I need to call a function to, as you mentioned, set the status of the module? Will this turn on the Green “Module Status” LED?



I am starting to wonder if we are trying to answer the wrong question here, this looks like an XYproblem. What exactly are you looking to do with turning on the LED? Why are are you trying to control the LED’s?

They are almost never controlled by the host application the host would set the status then the Compactcom is going to set the LED’s as necessary. There are no functions available in the API to directly control the LED’s. If the host is controlling the LED’s this would be due to them being connected directly to the the host processor, in this case it is setting the necessary LED state depending on the status.

LED1 and LED2 are going to be for the Network especially for EtherCat you do not alter how they work. EtherCat requires the LED’s to be in particular states to pass conformance. LED3 and LED4 are going to be used for Link and ACT. I would also not recommend altering these. I’m not sure what the requirements are for conformance but typically these do not get re-purposed.

Are you using our host application or writing your own? What do you have working with the host process? As I mentioned there is no explicit function to set the LED’s. There also isn’t an explicit function to set the module status, the Ethercat slave controller state is managed internally. The expectation would be that your host is stating up the Compactcom.



Look at my original question: “I have seen the Module Status LED light red, but I have never seen it light green. Under what condition will it light green?”

All I am asking is, given that the “Module Status” LED is two colors, red and green, under what conditions, if any, does it light green? Or, put another way, why have a green/red LED if only the red portion is lit?


The “Module Status” LED is the EtherCAT “ERR LED”. For EtherCAT the green portion of this LED signal is not used.

The green LED used in the “Module Status” is used for other network types.