A question for the RM programming experts.

[NormanQ4]

I am currently trying to get a basic program to work but the issue I have is in the playback, where some points fail to function.

These are pairs of points that are connected to the same decoder port, one pair as a crossover the other as a passing loop with one fictitious point number.

Sometimes they work and sometimes they don’t.

I get the warning that there isn’t a 2 second gap between these points firing which is obviously due to them being via fired the same decoder port.

Has a work around been found that allows the points to function correctly every time? 

[Fireman_Ian]

I think there is a line in the "ini" file which can be changed to fire the points twice but I cannot remember which line, I am sure someone will give more info on this.

 

What I used to do in the early years of railmaster was put the points fireing command in twice with a one second gap, then if the Elite missed the first command it usually got the second one. If the Elite got both commands it did not matter.

[RDS]

Ray is our Programming Expert, hopefully he will be along soon to offer a solution.

[Chrissaf]

Page 33 of the RM manual. Note however that Double pulse=1 is the default setting, unless it has been manually changed.

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Question seeking clarity:

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When you say two sets of two points connected to the same decoder port. Do you actually mean two sets of two points connected to the same decoder (one pair on each of two physical ports) or do you mean (as your sentence suggests) that ALL FOUR point motors are connected to the SAME physical port. If you do have four points on one single port, it is no wonder that they misfire.

[NormanQ4]

Naughty, naughty Chris, you're not paying attention

I didn't say that the points misfired when the program was being recorded, but I did say that there was a problem when replaying the program.

"the issue I have is in the playback".

"Sometimes they work and sometimes they don’t."

I think that it can be taken as given that the points have been wired correctly since the program has been recorded without any problems.

[St1ngr4y]

Hi Norman,

When I started recording programs, like you, I found that occasionally, certain points failed to fire within programs. Sometimes it was simply because of a sticky point motor, but more often than not it was the sequence of firing the points. I found that repeating the point change commands after adequate recharge times, improved the performance. I am assuming that your decoders are R8247s, which only have one CDU which is shared by all four ports on the unit. This means that whenever one port on that decoder is fired, a 2 or 3 second delay is required to allow the CDU to recharge, before any other port on the same decoder can be fired reliably. If you only have one decoder, then leave say 3 seconds between each port firing. I've always been a bit dubious about the INI file entry "DOUBLE PULSE", because if you think about it, all that RM and your Elite or Elink can do is to send two DCC commands to the port. It is then up to the decoder to convert each one into a separate discharge of the CDU, and if the second one occurs too soon after the first, then there won't have been enough time for the CDU to recharge enough to provide a reasonable "kick" to the point motor for the second one. Having said that, I have DOUBLE PULSE=1 set in my INI file as it doubles the chances of the decoder receiving the instruction to fire a port in the first place i.e. in case any external interference corrupts the first DCC packet in any way.

Ray

[NormanQ4]

Thanks for the insight Ray.

I already have double pulse set but I didn't know that the R8247 only has one CDU.

I'll see if I can increase the timing between the firing since the problem is occurring with pairs of points connected to the same decoder.

Would I be right in assuming that since two points are being fired on each occasion at the same time this would result in a greater discharge and therefore recovery than if only one point was being fired?

Unfortunately all but two of my points are in pairs so greater attention to timing will be required..

[37lover]

Norman,

There are other manufacturer's accessory decoders with multiple in-built CDU's but Forum rules mean you'll have to find them yourself. Obviously will incur extra money and a bit of hassle fitting/programming but might be something for you to consider.

[96RAF]

Worse case scenario an R8247 should recharge from flat in under 3 seconds, so factor that into your program and see if it helps.

 

Another tip is if you have more than one R8247 then arrange the route so they fire alternately, thus giving each a chance to recharge while the other one is working.

Rob

[Chrissaf]

Also to note in addition to what Rob wrote.

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The R8247 only listens to DCC packets, it doesn't speak DCC packets. Thus you can have two R8247s configured with the same four port DCC address range if you want two ports on different decoders to fire simultaneously from the SAME DCC Port Address command. Obviously you can't have two ports on the same R8247 with the same DCC address.

[St1ngr4y]

Would I be right in assuming that since two points are being fired on each occasion at the same time this would result in a greater discharge and therefore recovery than if only one point was being fired?

 

The R8247 is unaware of how many points are attached to each port. The discharge should be the same for one point as for two and I would guess that the recovery time should be the same. Maybe someone with greater electronics expertise than mine can confirm this?

 

Ray