# ESC feedback

Source: https://forum.modalai.com/topic/1519/esc-feedback
Category: ESCs, Sensors and Accessories (https://forum.modalai.com/category/15/escs-sensors-and-accessories)
Tags: esc
Posted: 2022-11-03 00:26:03 UTC by Moderator (ModalAI staff)
Replies: 5 · Views: 2097

## Moderator (ModalAI staff) · 2022-11-03 00:26:03 UTC

Question from customer - the modalai esc is working fine when commanded, but the RPM and voltage feedback is not available. I have attached a screenshot of the modalai_esc status which shows the feedback isn't coming in. I checked the connections, they seem fine. 

![esc-feedback.png](https://forum.modalai.com/assets/uploads/files/1667435162423-esc-feedback.png)

## Reply by modaltb (ModalAI staff) · 2022-11-03 00:44:00 UTC

Hello, thanks for reporting.  Good news is we already have a fix in for via this commit:
https://github.com/modalai/px4-firmware/commit/577fec3b9a843b709086fc07b913b2c194367e10

It's slated to release in our next platform release (platform release 0.9), I can't mention the release date, as the release gods will then delay it... but we are getting close!!!!!

There are pre-release channels available for developers, captured here: https://docs.modalai.com/configure-pkg-manager/#dev

## Reply by vivek rk · 2022-11-17 19:16:13 UTC

Hey, thanks for that. I was able to pull the voxl-dev branch and got it working on the VOXL2, I can see the feedback of the RPM on the mavlink topic SERVO_OUTPUT_RAW. But the frequency is at 10Hz. 
When I try to use the following command 

mavlink stream -u "port_number" -s SERVO_OUTPUT_RAW -r 100 

I get an error **stream SERVO_OUTPUT_RAW not found**

From the uart_esc code in px4-firmware I see that the uorb topic thats being used for RPM information is ESC_STATUS. And doing the following commands yields no result. The frequency is still 10Hz 

mavlink stream -u "port_number" -s ESC_STATUS -r 100

mavlink stream -u "port_number" -s ESC_INFO -r 100 

Is there anything I can do to increase the frequency of the message ?

## Reply by modaltb (ModalAI staff) · 2022-11-22 01:33:55 UTC

Sorry for the lag, what if you use `px4-listener esc_status` ?

If it's showing up there, likely we need to modify something to get this offboard....

## Reply by vivek rk · 2022-12-07 22:07:19 UTC

So when i try px4-listener it says command not found. 

The command that works is 
**listener esc_status** 
This produces the following resutls 
**never published**

But after some investigation, the uorb topic with the rpm information is 
**actuator_outputs** 

I can read the output 
![a26b73fe-2f2e-4d11-af51-708a2d939978-image.png](https://forum.modalai.com/assets/uploads/files/1670449856126-a26b73fe-2f2e-4d11-af51-708a2d939978-image.png) 

This topic is being published at 500Hz 

I tried to increase the rate of the following mavlink topics 

**mavlink stream -u 15446 -s actuator_output -r 100**
**mavlink stream -u 15446 -s ACTUATOR_OUTPUT -r 100**
**mavlink stream -u 15446 -s actuator_outputs -r 100**
**mavlink stream -u 15446 -s ACTUATOR_OUTPUTS -r 100**

Which results in the following error message 
ERROR [mavlink] stream ACTUATOR_OUTPUTS not found (same for all other)

## Reply by vivek rk · 2022-12-07 22:25:29 UTC

Fixed the problem, the mavlink stream name is SERVO_OUTPUT_RAW_0. 

changing that to 200Hz gives us the RPM feedback at 200Hz on mavros