Tinkerkit DMX Master shield not working.

Hi!
I’m trying to control 8 Alkalite Versabar 270’s with an Arduino Uno and a Tinkerkit DMX Master shield.

I’ve tried using both the DMXSimple and DMXMaster libraries, (which are virtually the same anyway).
I’ve tried both the example codes from the library, and stuff I’ve written myself. All have exactly the same result.

The Versabars are set to DMX-mode and receive on 5-channels (1:R 2:G 3:B 4:Brightness 5: Strobe) on DMX address 1.
When they’re not receiving DMX, the DMX status led is not lit, and they do their default chase.
As soon as i send a DMX signal, the DMX status led is lit, and the display says it’s receiving DMX.
However, the actual information I send doesn’t seem to make a difference. What happens is that the versabar goes out of chase mode, and displays a random color, chase or strobe effect.
No mather what I send after the initial signal, the versabar won’t respond.
I’ve made sure the DMX line is properly terminated as well.

I’ve read somewhere that the DMX Master shield doesn’t send “good” DMX signal. Maybe this is a case of Versabars being picky? I will try the shield on some other lights tomorrow just too try and exclude that the arduino/shield is broken. I’ll report back.
Any help is greatly appreciated!

This is the code I’m using (I’ve tried addressing channel 1-5 with different values in the 0-255 range, both seperately and together):

#include <DmxSimple.h>

void setup() {

  DmxSimple.usePin(3);
  DmxSimple.maxChannel(5);
  
}

void loop() {
  int brightness = 255;
  DmxSimple.write(1, brightness);
  delay(10);
  }

}

Ok. This is embarrassing, but I just got it working!
I had to change the DmxSimple.maxChannel-value to above 32 for it to work as expected.
Apparently it got too frequent updates or something like that.