Zimo decoders, Traincontroller and accurate stopping

[WIMorrison]

Robert,

 

After a bit of hassle with a MX638 decoder which refused to update (though another 2 did update!) I have managed to update 11 locos this morning (MX616, MX617, Mx618, MX622 and MC638) and the measured max speed is within 1.5mph higher for forward and reverse on all locos after upgrading. I think this could because of a range of issues from temperature to loco use since last measured, therefore I don't consider this an issue as it is many months since some were last measured.

 

The one MX638 that wouldn't update needed resetting to defaults, and even then it wouldn't update without a forced Ctrl+Alt+Z update - strange, but this has been the problem loco

 

All in all I don't see the issues you are describing but I am not upgrading from so far back. The older was one loco on v37.2

[RFS]

1 hour ago, WIMorrison said:

Robert,

 

After a bit of hassle with a MX638 decoder which refused to update (though another 2 did update!) I have managed to update 11 locos this morning (MX616, MX617, Mx618, MX622 and MC638) and the measured max speed is within 1.5mph higher for forward and reverse on all locos after upgrading. I think this could because of a range of issues from temperature to loco use since last measured, therefore I don't consider this an issue as it is many months since some were last measured.

 

The one MX638 that wouldn't update needed resetting to defaults, and even then it wouldn't update without a forced Ctrl+Alt+Z update - strange, but this has been the problem loco

 

All in all I don't see the issues you are describing but I am not upgrading from so far back. The older was one loco on v37.2

 

Thanks for that. This is how I see the problem. I've created a simple TC switchboard below that contains just the 3 blocks and two train definitions so I can run this as a test with nothing interfering. The two engines are identical Bachmann 4-CEPs, 7113 with a Lenz Silver21+ decoder and 7141 with Zimo MX638. The two schedules are shuttles - 2block is a shuttle between the station block on the right and the previous block, and 3block goes one block further back. The 4-CEPs are 42 inches long and all 3 blocks are at least twice that so there's no problem with the units getting to speed before moving to the next block. Max speed is set to 40 MPH for the test.

 

7113 stops at exactly the same point on return to the station on both schedules, but 7141 only does that on the 2block schedule. On the longer 3block schedule it stops 10-12 cm short. I have 8 Zimo-fitted locos on 40.5 at present with MX600R, MX623R, MX634D and MX638 and all do exactly the same. Identical Lenz-fitted locos do not exhibit this characteristic. So I'm waiting to see if it's possible to downlevel the firmware before I can take it any further.

 

 

[WIMorrison]

Hmm, not sure that I can do anything to help as I am not seeing these issues.

 

I use an almost identical setup to speed measure the locos and calibrate stopping as I use a totally separate bit of track with 3 feeebacks. 
 

I also use the same bit of track to update the software on the locos. When I upgraded the firmware I did check on the top, middle and bottom speeds to see if they were substantially the same and they are. I then check the stopping position using a shuttle route and again there is no substantial difference, certainly no difference that isn’t what I would do expect to see in normal operations.

 

I may have corrected the issues you see earlier and have forgotten the details as I do have a vague memory of some locos changing stopping position a long time ago, however I generally run the ITrain beta software as a tester and I would probably have put any issues down to that than anything in the decoder update - if I even associated the two of them.

 If 

[RFS]

After a full week, I'm still waiting for a response from Roco regarding my inability to upgrade decoders with a lower level of firmware. But I have found an issue which may be relevant.

 

I profile my locos using 3 consecutive blocks with occupancy detectors. The measuring block is 75 cm and the run-in/run-out blocks are 60 cm which is long enough for the loco to reach max speed for the speed step being measured as long as F4 is turned on. I re-tested one loco (actually a Bachmann 2-HAP with MX638) for just the top speed step 126 and TC records the speed as 69 MPH consistently. However, if I move the train a long way back (at least 5m) so that it has a long run to reach the measurement block, TC records the speed as 76 MPH. Again this was consistent over several runs.

 

The recent changes to CV 5 handling in Zimo firmware, which resulted in my having to reprofile all of my Zimo-fitted locos, looks like being where the problem may have arisen. I will respond to Zimo shortly and see what they say. 

 

 

[Andymsa]

17 hours ago, RFS said:

After a full week, I'm still waiting for a response from Roco regarding my inability to upgrade decoders with a lower level of firmware. But I have found an issue which may be relevant.

 

I profile my locos using 3 consecutive blocks with occupancy detectors. The measuring block is 75 cm and the run-in/run-out blocks are 60 cm which is long enough for the loco to reach max speed for the speed step being measured as long as F4 is turned on. I re-tested one loco (actually a Bachmann 2-HAP with MX638) for just the top speed step 126 and TC records the speed as 69 MPH consistently. However, if I move the train a long way back (at least 5m) so that it has a long run to reach the measurement block, TC records the speed as 76 MPH. Again this was consistent over several runs.

 

The recent changes to CV 5 handling in Zimo firmware, which resulted in my having to reprofile all of my Zimo-fitted locos, looks like being where the problem may have arisen. I will respond to Zimo shortly and see what they say. 

 

 

What is the function of F4 that your using, is this something relevant to Zimo, as I never had to turn on F4 with the few Zimos I have to affect max speed. Possibly I may have missed something here.

 

good point regarding the run out on TC next time I do a calibration I shall try extending the run outs, but I do tend to notice at higher speeds the run out does tend to creep more longer due to the momentum of the loco.  

[WIMorrison]

F4 is the default key used by Lenz for Direct Control i.e. the values you have set in the decoder for acceleration and braking are disabled when this function is latched on.
 

Many people, myself included, set this same key in Zimo decoders and also F3 which is the default by Lenz for Shunting speed.

 

iTrain automatically disables the acceleration and braking values set within the decoder when doing speed measurements.

[jpendle]

5 hours ago, WIMorrison said:

F4 is the default key used by Lenz for Direct Control i.e. the values you have set in the decoder for acceleration and braking are disabled when this function is latched on.
 

Many people, myself included, set this same key in Zimo decoders and also F3 which is the default by Lenz for Shunting speed.

 

iTrain automatically disables the acceleration and braking values set within the decoder when doing speed measurements.

Hi Iain,

 

This is slightly off topic but the whole "Direct Control" thing in the iTrain manuals has been bugging me for a while.

I cannot find any mention in the Zimo manuals of a Direct Control feature, so how have you got this to work?

I've been setting CV's 3 & 4 to 0 for my speed measurements.

 

Thanks,

 

John P

[WIMorrison]

@jpendel 

 

 

Set these in your Zimo decoders

 

[RFS]

Well finally got the Z21 to downlevel the firmware but it was a bit of a struggle. I've had to set up a piece of rail close to the Z21 with wires only a couple of feet long. Now a Hornby T9 with Zimo MX600R works, but not the Bachmann EMUs. For these I've had to take the decoder out and put it in a Bachmann C class which has a 21-pin decoder in the socket. I assume the Z21 doesn't like anything with lighting circuitry, but I did flash them all first time around without having to do this!

 

I originally bought 7 MX600Rs a few years ago and all had 31.63 level firmware. The earliest I'm able to go back to is 37.1 as none of the Zimo download files have the MX600 on them. With 37.1 installed the T9 now performs perfectly! Stops in the right position every time, whether running long or short schedules. Then I tried to do a bit of detective work for Zimo to see what version introduced the problem. With 37.8 the T9 overshoots the stop marker, with 39.0 it stops up to 25cm short and 40.1 is basically the same as 40.5, ie OK on the short schedule but stoping 10 cm short on the long.

 

I've since flashed the two MX634Ds in Bachmann 2-EPBs back to 37.1 and these now work fine too. 

 

Stephan from Zimo did come back to me and say the best way of limiting max speed on their decoders is not to use CV 5 but instead use CV 57. I did try this while still on 40.5 and it did improve things. I set CV3=0, CV4=0, CV5=1 and CV6=1 and then found that CV57=70 gave a top speed of 70 MPH which is the most I need. On the schedules, they were OK on the short but overran about 2-3 cm on the long. That's quite acceptable and I will stick with that with the 4-CEPs as I really don't want to take their bodies off too! But I prefer the 2-EPBs on 37.1 as they seem more accurate.

 

This was the profile from the 2-EPB using CV 57=70 on 40.5 firmware:

 

 

Compare this with my other 2-EPBs which have Lenz Silver21+ decoders -

 

 

A more even profile it seems to me. Still toying with the idea of getting a couple more Lenz decoders for these.

 

Seems Zimo have been making changes to Back EMF and motor control and these are causing the issues. The Lenz firmware is the latest with version 14 which has a build date of September 2011. Seems like Lenz got to this version, found it was OK and have left it alone since. I have 85 locos altogether - 10 with Zimo and 75 with Lenz. Just glad those numbers aren't the other way round!

[RFS]

Got round today to sorting two problem locos which weren't running well with their Zimo MX600R decoders following the firmware upgrade to 40.5 from 31.63. They needed re-profiling under TC, a requirement that was also needed because I had increased track voltage from 15.5v to 18v. Firstly both decoders were taken back to level 37.1

 

This is a Hornby West Country 34008 whose profile originally looked like this:

 

 

 

Performed OK but does have the typical S-shaped profile that most Zimo decoders show.  Following advice from Zimo to set CV5=1, CV6=1 and use CV57 to control max speed I got this with CV57=0 as a first attempt:

 

 

Not pretty! Went back to CV5=170 and CV6=90 to get this:

 

 

Much better but a more pronounced S-shape. Will leave it at that for now as the loco seems to be OK.

 

The second loco is a Bachmann Standard 4MT 75069. The best I could get with the Zimo was this:

 

 

That's not good either! Replaced the decoder with a Lenz Standard+ and this is the result with CV5=220 and CV6=48 to get max speed at 60 MPH:

 

 

Will be sticking with Lenz decoders from now on for any new stock!

 

 

[jpendle]

Hi,

 

FWIW, my N Gauge locos with Zimo decoders have curves that look like your Lenz decoders.

The only difference that I can think of is that I don't set CV6, I leave it as the Zimo default (1), I then have CV2 set to around 20 and CV5 set to around 120. (This is for N Gauge Diesels).

 

I did try using CV57 instead and didn't get good results.

 

Regards,

 

John P

[WIMorrison]

@jpendleI do the same and get the same results as you - a pretty well straight line from CV5 max speed down to CV2 min speed.

[RFS]

I think a lot can depend on the loco. With the majoirty of my locos being Lenz-fitted, I've got into the habit of leaving CV6=48 (Lenz default) and bringing CV5 down till max speed is no more than 60 or 70 depending on loco.  Then I get a more or less straight line profile as above. That doesn't work with Zimo decoders though. An MX600R in a Hornby T9 seems to work better here, with CV5=120 and CV6=60:

 

Edited September 20, 2021 by RFS

[melmerby]

1 hour ago, RFS said:

Got round today to sorting two problem locos which weren't running well with their Zimo MX600R decoders following the firmware upgrade to 40.5 from 31.63. They needed re-profiling under TC, a requirement that was also needed because I had increased track voltage from 15.5v to 18v. Firstly both decoders were taken back to level 37.1

 

This is a Hornby West Country 34008 whose profile originally looked like this:

 

 

 

Performed OK but does have the typical S-shaped profile that most Zimo decoders show.  Following advice from Zimo to set CV5=1, CV6=1 and use CV57 to control max speed I got this with CV57=0 as a first attempt:

 

 

Not pretty! Went back to CV5=170 and CV6=90 to get this:

 

 

Much better but a more pronounced S-shape. Will leave it at that for now as the loco seems to be OK.

 

The second loco is a Bachmann Standard 4MT 75069. The best I could get with the Zimo was this:

 

 

That's not good either! Replaced the decoder with a Lenz Standard+ and this is the result with CV5=220 and CV6=48 to get max speed at 60 MPH:

 

 

Will be sticking with Lenz decoders from now on for any new stock!

 

 

My findings exactly.

The few locos I have with Zimo decoders have a pronounced "S" shape but Lenz are pretty well dead straight.

The best I did with a Zimo decoder was to use the custom speed table and work out a correction for the S shape still not perfect.

 

AS  comparison to eliminate motor etc. variations I have two Hornby Large Praries, one with a MX600, one with a Lenz Standard + V2.

The Lenz is straight, the Zimo has the S shape but not as pronounced as the MX618N18 in my Dapol 43XX (the one with the custom speed table).

 

Dapol 43XX with MX618N18, profile and the custom speed settings to get it:

 

 

Mentioning T9s here's mine with a Lenz Standard + with settings of Start = 1, middle = 91, TOP = 180: