0

MD4 problems when backlight is 70% or above.

Niklas 6 years ago in Master modules / MD4 updated by Gustav Widén (System support) 6 years ago 7
Hello,

If you adjust backlight in the MD4 higher then 70% the screen brightness gets unstable starts vary in brightness up and down.  
Under review
What SW version are you using on the MD4? We made some improvements to the backligth in version 3.15
Also, do you have a channel to control the backlight?
And is the screen-saver function on?
We have seen a problem with the screen saver interfering with the channel control of the backlight, but I believe that problem should be solved in 3.15
Hi Gustav,

I loaded the application with IQAN design 3.15
No channel to control the backlight, only via menu system.
Screen-saver is off

How do you supply the MD4 (e.g. battery on the vehicle or a fixed power supply on the bench) when you see this?
What is your supply voltage?

The MD4 has a function that automatically reduce backlight at supply voltage <14V. It drops linearly down to 50% at 12 V.
There is some hysteresis on the backlight reduction function, to avoid flickering due to small variations in supply voltage.
Gustav,

I use a transformator converting 230VAC into 12VDC 1A

Can this be the reason?
Maybe.A 12 V supply with a capacity of 1 A should be enough to power the MD4.
Is the MD4 the only device you power via the 12 V supply?

With the backlight reduced to 50% (done automatically by the SW), the MD4-7 draws about 600 mA @12V.
Current consumption increase to about 750 mA @14 V (full backligth available), and then drops off again as the supply voltage increase.

One idea could be to measure the supply voltage via the MD4 using the module diagnostics to see if it is stable. For this, it is best to use IQANrun or a MDGN on a display page, (the MD4 module info in the menu system does not update automatically)
Hello Gustav, 

I change to a 24VDC 3A supply and now it works fine! Also no problems when using the power supply on the machine. 
Thank you Niklas, good to hear that the problem you had was solved. It seems as if it was due to insufficient current capacity on the power supply.