I have an Atlas GP38 and GP9 that I plan on running MU’ed as my local freight. I’ve managed to match the top speeds to ‘close enough.’ The GP9 has the scale speed motor and a TCS ASD4 decoder. The GP38 has the high speed motor with a Digitrax DN163A0 decoder. I’m using JMRI connected to my Zephyr to program the decoders. I am having problems getting both loco’s to start moving at the at the same throttle setting. I’ve been changing CV02 on both locomotives but have only been able to make the GP38 start at a higher voltage. I haven’t been able to change when the GP9 starts. Are there any other CV’s I should be looking at? Another odd thing I’ve encountered is that when I use my Zephyr to consist them together, both loco’s run as expected. However, if I use JMRI to consist the two loco’s, the GP38 doesn’t respond till about the throttle is up to 70% or so and then tops out about ¼ of what the top speed is when not consisted. I’ve looked though the JMRI tabs and don’t see any CV’s that look like they modify the speed curve when in a consist. Does anybody have any idea why this is happening? Both locos have BEMF enabled, but now that I think about it, I can’t remember if the GP38 with the Digitrax has BEMF disabled when in a consist. I started with BEMF disabled with both and even more problems trying to get them to run together. Any help or insight would be much appreciated.
I don't have any experience with TCS decoders, but I do know that with Digitrax decoders, when using Bemf Compensation, you generally leave CV2 set to 0 and adjust the Bemf settings to get the locomotive to just barely start moving at speed step 1. The default Bemf settings for Digitrax turn off Bemf compensation when the decoder is in an Advanced consist. The Zephyr defaults to Command Station consisting, which does not turn off Bemf compensation(the decoder doesn't even know that it is in a consist). When you consist them with JMRI, it is using advanced consisting, so the Digitrax decoder is turning off Bemf compensation.
With Digitrax decoders, CV 57 controls the BEMF level. The factory setting is 6, which means that the BEMF normal setting is 6, but the advanced consist setting is 0. For advanced consisting CV 57 needs to be set to hex 66 (102 decimal) to enable BEMF in advanced consisting as well as normal operation. The right hex digit is the normal BEMF level, the left is the advanced consisting BEMF level. (one reason for Digitrax putting the hex conversion table in the decoder manual)
I have three TCS decoders that I do not consist, period. One is a switcher but the other two are road units (GP30 and RS4/5) that would be nice to have in consists. I gave up on using these TCS decoders for consisting and plan not to ever buy a TCS again.
