Function voltage change

[gooderz]

I Recently installed a Zimo MX645 in my Bachmann cl37. I had to install lighting into it and set up the headcode display as F0 (as you'd expect). But I installed the Tail marker lights Aux 2&3 so that they can be independently controlled (on F8 which was designated for cab lights in Digitrain's manual) with out the need to have a switch to turn the red lights off like many of bachmanns models do. The thing is, the LEDs I installed are far too bright, I am aware i can dim them by altering a CV value. Can anyone advise me which CV(s) to alter please.

 

Note: I don't want my head code to be dimmed

 

Cheers

 

Jamie

[pauliebanger]

Jamie,

 

From what you have said, you have everything working as you wish except for the brightness of the red LEDs

 

You could install higher value series resistors to reduce the current to the red LEDs.

 

If you wish to dim the reds alone by using CVs, here's what you need to do.

 

Set up a 'dimming mask' to maintain brightness on your headcode lamps:

 

CV114 = 3

 

Then 'dim' the red LEDs using Pulse Code Modulation (PCM) to restrict the current and dim the output:

 

CV60 = X, where X is value determined by trial and error. The range of values is 0-255, lower numbers give reduced brightness.

 

Suggested values; try around 30 to 60. The exact figure will depend on the resistor size already in circuit.

 

Just a cautionary note.

 

This system works fine, but at very low values the PCM duty cycle will be short in comparison to the time that power is in the 'off' portion. This normally has no visible effect on your eyes due to latency, but it is often picked up by video recordings. Have a look at some YouTube videos,the ones with regularly flickering lights are probably dimmed with PCM.

 

A few people report being able to detect such flickering with the naked eye.

 

Worth thinking about if you have health issues which may be affected by flashing lights!

 

In contrast, adding a series resistor will dim the LEDs but not produce flickering, subliminal or otherwise.

 

Kind regards,

 

Paul

[gooderz]

Paul,

 

Many thanks for this, I will give this a try when I get back to my loco on Friday.

The resistor I fitted to that particular circuit was 1K.

 

Cheers

 

Jamie

[melmerby]

Jamie,

 

From what you have said, you have everything working as you wish except for the brightness of the red LEDs

 

You could install higher value series resistors to reduce the current to the red LEDs.

 

If you wish to dim the reds alone by using CVs, here's what you need to do.

 

Set up a 'dimming mask' to maintain brightness on your headcode lamps:

 

CV114 = 3

 

Then 'dim' the red LEDs using Pulse Code Modulation (PCM) to restrict the current and dim the output:

 

CV60 = X, where X is value determined by trial and error. The range of values is 0-255, lower numbers give reduced brightness.

 

Suggested values; try around 30 to 60. The exact figure will depend on the resistor size already in circuit.

 

Just a cautionary note.

 

This system works fine, but at very low values the PCM duty cycle will be short in comparison to the time that power is in the 'off' portion. This normally has no visible effect on your eyes due to latency, but it is often picked up by video recordings. Have a look at some YouTube videos,the ones with regularly flickering lights are probably dimmed with PCM.

 

A few people report being able to detect such flickering with the naked eye.

 

Worth thinking about if you have health issues which may be affected by flashing lights!

 

In contrast, adding a series resistor will dim the LEDs but not produce flickering, subliminal or otherwise.

 

Kind regards,

 

Paul

Many multi digit LED displays are strobed so that only one digit is on at any time.

Apart from reducing power consumption it means only one decoder is required for all the digits!

Normally the eye doesn't notice that but video recordings usually show it up.

 

Keith