Hi There, I have built a custom DCC Servo decoder designed by Terry Chamberlain. https://www.a-train-systems.co.uk/projects.htm#QuadServo . It uses his custom sketch for control, and also upload the standard NMRA DCC file to the sketch. He uses his own software with NCE system to read and write CVs with his own system I have a Digitrax system so his software won't work for me. I AM able to write to the decoder with both JMRI and Digitrax. I am told that you can read the CVs with the Digitrax system one CV at at time from the programming track. I currently don't have a throttle to test this, as my DT602 is in for repair, and I only have a DT100 available. I am unable to read CVs using JMRI. I receive (308) "No Locomotive Acknowledge" errors returned from JMRI. I connect JRMI with a Digitrax PR3. Com 3. DCS200 connected to programming track from the front of the DCS program A and B connections. I power the Arduino Servo Decoder using the USB port, so it stays powered, instead of only powering when DCC send program info. I have read through the article on the attached website, and understand, that the author was also not able to read with JMRI, but was able to read with other systems. Does anyone with JMRI and Arduino experience have any suggestions to help me get reading CVs with JMRI working?
"one CV at a time" rings a bell... There is a setting in JMRI DP to read CVs in different ways (e.g. direct, paged, etc., IIRC) Not exactly sure what they mean, but try the different ways allowed. Hope this helps...
Build Your Own Quad Servo DCC Decoder – Part 2 : page 9: Reading and writing of CVs values via a programming track (Service Mode) can be done using a handheld controller connected to all major types of DCC system but (unless someone can tell me differently) not from JMRI Decoder Pro which simply decides that the decoder is not a locomotive and refuses to proceed further. However, if you have any type of NCE DCC system plus a Windows computer, my own application, A-Track (www.a-train-systems.co.uk/atrack), will happily read and program the QSDD CVs and allow you to save a record of them to file.
Indeed you can read individual CV's in JMRI directly without acknowledge requirement (hence without the decoder needing to be a mobile attached to a loco).
The Digitrax DT100 throttle can read back CVs. I think the issue with his description of JMRI not being able to read it is if you have it set up as a stationary decoder in JMRI it won't let you try to read it, but if I remember correctly (it's been a while since I've used JMRI) there is a separate CV program/read function that you can use. The 308 error does sound like it JMRI is attempting to read the decoder but not seeing the acknowledgment pulse from the decoder. Do you have the keypad for the decoder hooked up? The decoder flashes the LEDs on the keypad board to generate the acknowledgment current pulse.
Just to be clear, JMRI can only read CVs through the DCC system to which it is connected, whether it be Digitrax, NCE, SPROG, etc. However, JMRI's display screens show you the meanings of the bit/field values in plain language, not binary or hexadecimal data. You don't need to perform your own arithmetic or boolean logic to read or write the registers with the settings you want. The display screens are custom developed for the various decoders to make it easier to understand and configure the decoders' programmable options. Furthermore, JMRI can copy and save the settings for each of your locomotives, so if after you have carefully configured your locomotive to the Nth degree, and you need to restore it after decoder looses its mind (or you want to duplicate most of the settings on another locomotive with the same decoder), it is a simple task in JMRI.
