Refresh rate from DMX controller - E1.20 RDM (Remote Device Management) Protocol Forums

Nelly · November 21st, 2017

Hello there,

I have bought an Arduino board and a DMX shield to get the DMX functionalities to the Arduino. I have tried to connect the DMX shield to a LED driver that runs DMX but it seems like the LED driver doesn't get any DMX signal at all. Then I tried to connect the DMX shield to a Lightcorder (a device that can read the DMX signal). The lightcorder reads the DMX signal without any problem at all which tells me that the problem is between the shield and the LED driver.

I have also tried to measure a DMX signal (The LED driver can see this signal) send from another DMX controller to the LED driver and the only difference between the two signals that I know of is the refresh rate. The DMX shield is transmitting with a refresh rate of 19-20 Hz and the other equipment is transmitting with 40-41 Hz. Can this be the problem? Is it possible that the LED driver is made in a way that it can't receive DMX with a refresh rate that is 20 Hz?

Best regards
Christian

ericthegeek · November 21st, 2017

The refresh rate ("Hz") tells you basically nothing. What matters is the timing of the individual elements within the DMX packet. We can't really answer your question without having a lot more details about the setup. You'll likely need an Oscilloscope or DMX tester to get much further.

Nelly · November 22nd, 2017

Hello again,

Thank you for the answer. I'm sorry for the lack of information but I'm quite new to DMX so I'm not 100 % sure about the information you want me to deliver. Can you please tell and I will find the information for you?

The Lightcorder is a kind of DMX tester as far as I know. It reads the signal and tells me the different DMX values on the different channels.

Best regards
Christian

ericthegeek · November 22nd, 2017

If you want to troubleshoot it, you'll need to look closely at the signal timing (min/max for break length, MAB length, byte spacing, etc.).

There are a lot of poorly implemented DMX devices out there. You may want to try a different LED driver.

Nelly · November 29th, 2017

Okay and thank you for the answer!

I know for sure that the LED driver is of high quality. I have tried 3 different LED driver models from EldoLED and one LED driver from KKDC. The LED driver from KKDC make the LED flicker, when it receives the DMX signal. Does that tell you anything?

I will try to get an oscilloscop to check out the timing of the signal.

Best regards
Christian

November 21st, 2017	#1
Nelly Junior Member Join Date: Sep 2017 Location: Denmark Posts: 7	Refresh rate from DMX controller Hello there, I have bought an Arduino board and a DMX shield to get the DMX functionalities to the Arduino. I have tried to connect the DMX shield to a LED driver that runs DMX but it seems like the LED driver doesn't get any DMX signal at all. Then I tried to connect the DMX shield to a Lightcorder (a device that can read the DMX signal). The lightcorder reads the DMX signal without any problem at all which tells me that the problem is between the shield and the LED driver. I have also tried to measure a DMX signal (The LED driver can see this signal) send from another DMX controller to the LED driver and the only difference between the two signals that I know of is the refresh rate. The DMX shield is transmitting with a refresh rate of 19-20 Hz and the other equipment is transmitting with 40-41 Hz. Can this be the problem? Is it possible that the LED driver is made in a way that it can't receive DMX with a refresh rate that is 20 Hz? Best regards Christian

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November 21st, 2017	#2
ericthegeek Task Group Member Join Date: Aug 2008 Posts: 379	The refresh rate ("Hz") tells you basically nothing. What matters is the timing of the individual elements within the DMX packet. We can't really answer your question without having a lot more details about the setup. You'll likely need an Oscilloscope or DMX tester to get much further.

November 22nd, 2017	#3
Nelly Junior Member Join Date: Sep 2017 Location: Denmark Posts: 7	Hello again, Thank you for the answer. I'm sorry for the lack of information but I'm quite new to DMX so I'm not 100 % sure about the information you want me to deliver. Can you please tell and I will find the information for you? The Lightcorder is a kind of DMX tester as far as I know. It reads the signal and tells me the different DMX values on the different channels. Best regards Christian

November 29th, 2017	#5
Nelly Junior Member Join Date: Sep 2017 Location: Denmark Posts: 7	Okay and thank you for the answer! I know for sure that the LED driver is of high quality. I have tried 3 different LED driver models from EldoLED and one LED driver from KKDC. The LED driver from KKDC make the LED flicker, when it receives the DMX signal. Does that tell you anything? I will try to get an oscilloscop to check out the timing of the signal. Best regards Christian