ESU Switch Pilot output pulse

[Michael_A]

I can programme this unit, but I cannot set the pulse output time.

 

The unit is very poor at throwing points, and, using a scope, I have figured out that this is because the output pulse is less thann100ms.

 

I tried to change this in RaiMaster, but it always comes bac at 16,000+ reading?

 

The switch on the ESU s left in 'user' mode.

 

Any ideas? 

[Chrissaf]

I am making the assumption that you have not connected the optional separate power supply to the ESU Switch Pilot as documented in section 6.5 of the manual. The ESU Switch Pilot does not have an on-board CDU (Capacitor Discharge Unit) thus its weak output to throw solenoid points is well documented on this forum.

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To the right of the Track connectors (still needed to provide the DCC control signals to the decoder) there are two terminals marked Pw A & Pw B. These optional power terminals supplement the ESU on board power, not substitute it. The DCC track connections are still required.

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/media/tinymce_upload/4e50c24b78404a3fa9bc3e0a55cc1477.jpg

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Note: there is a typo in the above image. The reference to Chapter 16 should read Chapter 17. The maximum power input ratings are 18 VAC or 24 VDC (regulated).

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You will find that if you provide these ESU Switch Pilot Pw A & Pw B terminals with a high current power supply source that can be either AC or DC. Then this will provide all the power oomph you need to fire even the most stubborn solenoids robustly. You need a power supply capable of supplying not less than 4 amps of between 18 and 24 volts. Most on here that are using these ESU Switch Pilots and their derivitives, have used a 19 volt Laptop power supply. These are very cheap on ebay and are high current 'switch mode' designs, meaning that they give off very little heat and provide high power in a small physical package very cheaply.

[Yelrow]

Michael A, hi, you have done better than many of us. I have never mahaged to get mine to work. john

[Chrissaf]

PS - I'm sure sometime soon, forum user RDS will be along and confirm for you that he is using these ESU Switch Pilots very successfully in conjunction with his 19 volt Laptop power supply connected to supplement the DCC track voltage.

[Michael_A]

I am using a seperate power supply, but power isn't the issue. Whether I power it from a seperate supply or from the track, I cannot change / set the pulse duration. I have even tried changing the CV values with my Elite directy, but it does not read them back, I just get XXX displayed.

 

What I have noticed in experimenting is that with the old Hornby point motors I get a nice 540ms pulse at 12v if powered from the track, and 16v if using the external 20v suply. So it seems something to do with the impedence of the new point motors, as with these I get a much lower voltage (about 8v) and shorter (about 80ms) pulse

 

Howvever, even with the old ones, I still can't change the pulse duration.

 

I will upload some oscilloscope images tomorrow.

 

[RDS]

... I'm sure sometime soon, forum user RDS will be along and confirm for you that he is using these ESU Switch Pilots very successfully in conjunction with his 19 volt Laptop power supply connected to supplement the DCC track voltage.

 

Sorry for the delay!

 

 I was just reading through the above posts and I was thinking that I should add a post to say that I have 5 of these units, operating 32 sets of points, using an old Laptop Power Supply.  Then I noticed Chrissaf's prediction!

 

I am delighted with these units but I have never had to alter (or even question) any of the pulse outputs.  With my separate power supply I have never had any problems although I did when I used to use the track voltage.  I did come to the conclusion though, that it was a power problem and not an ESU one.  My conclusion may have been wrong but I have never regretted it and I will be adding a 6th unit soon, to accomodate more points. 

 

All my points motors are Hornby R8014.  I never had any consistent success with the surface mounted R8243 ones.

[Fishmanoz]

The trouble with these devices is that they are far too capable and the complication that comes with that means many have had great difficulty in finding what they need in the 32 page manual and setting them up - see from John above.  That said, their addresses are set by learn mode programming, meaning it is simple once you get them into learn mode, which isn't done like most by setting a switch, rather pressing and holding a button until they flash at you.

 

Michael, it appears to be not unusual to be able to set CVs in accessory decoders but not be able to read them.  It tells you how to set pulse duration via CV3-6 on page 21 of the manual.  And I'd note the default in these CVs is 1 which gives a pulse duration of 130msec, the standard pulse duration for a solenoid.  Value of 2 gives you 260msec etc up to 64 is continuous.  Is this what you've been trying to do?

[Fishmanoz]

John, do you still want to try to get yours working?  I'm pretty sure someone can explain simply how to do it.  Trying to find out how in the manual was anything but simple.

[RDS]

I will try to find out how I did it - A post off this Forum I think.  It certainly was not from the manual.

 

Edit

Hmm, that's very interesting - It was a post from Michael_A, on 6th February 2014.

[Chrissaf]

Michael, although you say you are using a separate power supply and if I read your earlier reply correctly it is 20 volts. But humour me.....what is its full output specification....what current can it supply.

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If it doesn't say the current on the label, then what voltage and watts figure is quoted.

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As others have said, and RDS has confirmed. Using the right kind of separate power supply should provide a solution.

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The other piece of information you haven't stated is your point motor brand and part numbers that you are using. In general, the surface mount motors (as RDS hinted at) require more power. I know from personal experience the the Peco low power PL-10W variants (as opposed to the PL-10 & 10E variants) have higher resistance coils and need higher voltages to fire robustly.

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If you own an oscilloscope you obviously have an electrical background, but it is more helpful if you provide more detailed information about what you are connecting together.

[Michael_A]

So an update.

All is fine with the old type Hornby point motor!

Using the Elite I can write to CVs 3,4,5, and 6, and evn though when I try and read them back I get XXX, it does seem to accept the value (I wrote 10 to give 650ms pulse). I can also hear the PM connected to output 1 clicking as it writes. (Notes: switch in 'User' position, 20v 4A supply connected, for programming connected to programme output of Elite)

Whichever utput I now connect the old Hornby point mtor too I get a nice fat 650ms pulse. Whatever output I connect the new one too, I get a feeble short pulse.

Old point motor:

/media/tinymce_upload/abdd2f197ab4b4f5569d00daf5df809a.jpg

New point motor:

/media/tinymce_upload/80c1861092ccc473b449ff8fdb29c098.jpg

If I programme the CVs to 1, as suggested for Peco point motors, I get the same amplitude pulse with the old point motor, but only about a 50ms pulse (though it still fires the point) It makes no difference to the output using the new point motor.

 

The resistance of the old point motor is about 10 ohms across one coil, the new ones is about 2.5 to 3 ohms.

 

Conclusion, stay clear of the ESU with Hornby DCC............it's not worth the hassle!

[Michael_A]

Michael, although you say you are using a separate power supply and if I read your earlier reply correctly it is 20 volts. But humour me.....what is its full output specification....what current can it supply.

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If it doesn't say the current on the label, then what voltage and watts figure is quoted.

 

Hi, I just realisedmy posts were saving but need checing a sthey contain images. Just post the first one!

 

The supply is 20v 4 amps...... more than enough umph.....

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As others have said, and RDS has confirmed. Using the right kind of separate power supply should provide a solution.

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The other piece of information you haven't stated is your point motor brand and part numbers that you are using. In general, the surface mount motors (as RDS hinted at) require more power. I know from personal experience the the Peco low power PL-10W variants (as opposed to the PL-10 & 10E variants) have higher resistance coils and need higher voltages to fire robustly.

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If you own an oscilloscope you obviously have an electrical background, but it is more helpful if you provide more detailed information about what you are connecting together.

 

[Chrissaf]

Michael, you have quoted my whole post and your added text is lost in the yellow box. It is better for readers if you don't use the 'blue box white arrow' button as it it makes it easier to see what you have added if you post your text answer on its own (using the reply text box at the bottom on the page) as you have done in some of your previous replies.

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I sense some frustration in the way you have answered my question. We are only trying to help, but we are totally reliant upon what information you give us. The questions and answers help us to eliminate the possibilities. You still haven't told us what point motor products you are using (this was the second question in my last reply).

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Yes you are correct. Images are checked by Hornby forum administration before being published. This inevitably adds a delay particularly out of hours at weekends. The posts with images will most likely appear sometime Monday morning.

[Chrissaf]

Michael, going back to your original question as written.

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Your fundamental issue is not being able to modify the CV relating to 'pulse width'. Since, again you haven't told us which CV, I am assuming that this is CV3 (port 1) to CV6 (port 4). The ESU Switch Pilot supports multiple 'programming modes', that is to say "Direct Mode", "Paged Mode", "Register Mode" & "Programming On Main mode" (what Hornby call Operate mode). What modes have you tried so far (I acknowledge that most of these modes are not supported in RailMaster, but most are supported using the Elite). Again, you have told us you have tried programming the CV but you haven't told us exactly what methods you have tried using so far.

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Talking of RailMaster. Have you been trying to configure these CVs using the Accessory Decoder programming part of RailMaster or have you tried using the 'Locomotive CV' configuration window. I know from experience that you can use the 'Loco CV screen' to write decimal 8 to CV8 on a Hornby R8247 Accessory Decoder (on the programming track - Direct Mode). Have you tried writing to CV3 to CV6 on your ESU Switch Pilot using the 'Loco CV reading / writing screen'.

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The more information you provide, the easier it is to help.

[Michael_A]

Chris: I posted a full reply with screenshots from the scope. Awaiting moderator approval....

[96RAF]

Interesting that you are using a Picoscope Michael.

 

I am populating a link file for Picoscope that translates the binary code in the DCC trace into English, which become a free download to go with the software eventually.

 

Can I please ask how you hook up your probe. I have the probe on the Elite (whichever output I am measuring) A terminal and the ground clip on the B terminal and that gives a good signal trace.

 

Beware that if connecting multi channels to both the Track and the Boost outputs that on my Elite the Boost A-B was contra polarity the Track A-B output, hence why my Elite now has no programming ability as Boost and Prog share the same circuit via the relay you hear clicking.

 

Also be aware that we still haven't worked out how to safely connect both the scope and the Elite to a pc each by USB due to chance of mismatched potential on parallel ground paths. I wanted to do this to monitor RM traffic.

 

Rob

[Chrissaf]

Currently available PECO PL-10WE point motors have a DC coil resistance of about 12 ohms if that helps. The PL-10E coil resistance is about 4 ohms.

[Chrissaf]

Sorry to keep harping on about the power supply, but could it be that the power supply short circuit protection when firing <3 ohm coils is so efficient that the power supply is shutting down before enough time has passed to generate a more powerful pulse. What do you see if you monitor the direct power supply output with the scope when firing the two different solenoid coil types. If you see a similar reduction in pulse magnitude in the power supply output, then maybe a power supply with a less efficient short circuit protection circuit would help.

[Michael_A]

First question; I use a laptop with no power supply connected as I had the same earth path concern, so I simply connect the scope across the point motor coil. Probe to common, 'earth' lead to the the PM output. 

 

Second question, yes I could scope the power supply at the same time I suppose to see if it dips, but if I momentarily connect the power supply directly to the point motor it fires with a very satisyfing click! However, great idea, could be that the power supply dips and interupts the ESU electronics. I will scope that tonight....

 

I have just ordered an ADS8 and the ESUs are going on e-bay very soon, or I could try the Peco motors. To be honest, I think I was misled by Hattons and assumed through how the ESU was advertised that it had a built in CDU......

 

 

 

[Fishmanoz]

Agree with you concerning Hattons on this one.  They initially advertised the ESU as a replacement for the R8247 when that went off the market for something over 12 months.  The only commonality  between the ESU and the 8247 is they both have 4 ports for solenoids and are both DCC (have a DCC option for the ESU.

 

Good choice on the ADS-8.

[Michael_A]

So update. Neither point motor did the power supply I am  using to the extent that I would expect the ESU to limit.

20v 4A supply, new type point motor, dips to 16v from 19.....

/media/tinymce_upload/dfffdc5cad172094e88313bb9a775026.jpg

Old type point motor, higher resistance, dips less to about 18v from 19......

/media/tinymce_upload/0e5837d06463db6da5db7fd8c8806562.jpg

Even using the elite track feed, new type motor, still a good 24v p - p

/media/tinymce_upload/12e4a583494cf5741eb0da2c92ecdd90.jpg

Old type motor for completion of the set!

/media/tinymce_upload/8733c134fff57bc6274600f18135cca0.jpg

So as you would expect, the new hgh current motors dip the power supply more, but not enough in my opinion to affect the working of the ESU

Conclusion, ESU no good for new type Hornby point motors............

[Chrissaf]

Oh well, worth a try and looking at it.

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but not enough in my opinion to affect the working of the ESU

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I would tend to agree....

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Since you have already made the decision to replace with ADS and sell on, not really much more to add except better luck for the future and chalk it up to experience.

[Michael_A]

Would love to find a circuit diagram for the ESU, would love to know what they have done to limit the output current.....

 

I considered a whopping big cap across the 20V DC supply, but obvioulsy isn't going to help.....

 

Oh well, I will post some ADS-8 waveforms in due course.........

[Chrissaf]

I considered a whopping big cap across the 20V DC supply, but obvioulsy isn't going to help.....

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You never know, worth a try just for the hell of it if you have one to hand.

[Michael_A]

Nope! It didnt help! (6,800uF cap....)