Peco live frog points and Gaugemaster autofrogs

[ITG]

Hi

as a relative beginner, I’d like to check my understanding on the effect of using Gaugemaster autofrogs with motorised Peco live frog points. Logic suggest to me that if using a multimeter on these points, I should see an indication of DCC voltage between the outer rail of the point, and the frog section, only in the direction the turnout is set to. And conversely, no voltage on the other rail exit? And of course vice versa when the turnout direction is changed.

 

Its not that I have a particular problem with locos negotiating points (apart from one - see below), but on checking the one troublesome one, it then led to me checking others, and I’m not getting the results I might have expected. What would you expect to see? (Note that turnouts are modified by snipping the link underneath, and using IRJs on the two frog exit rails).
 

That then leads me to wonder if the terminals on the autofrog device have a right/wrong way round ( ie a +ve and a -ve) or doesn’t it matter?

 

Incidentally, one turnout, when switched to ‘turn’ is a problem for one loco - a class 08 shunter,, so a short wheelbase. It stalls at slow speed. No other loco does, and the Class 08 is fine on other points. I’m not unduly concerned as it’s highly unlikely that the Class 08 will actually venture over that point. But this particular turnout is one of those that does not give me the readings I expected.

thanks for any help.

Ian

Edited November 30, 2020 by ITG
Spelling correction

[norman]

OK it is important that you understand that the GM autofrog device senses a "short" and before your system reacts changes the polarity of the frog.  So in order to test whether its working correctly you need to operate a train through the point and check the polarity after you have done so.

If the train runs through the point both ways then it's safe to assume its working ok and no need for a meter.

The polarity will only change when the "short" is sensed not before.

I hope this helps!!

Norman

 

 

 

[peterfgf]

I've just connected two GM Autofrogs to a Peco Code 75 long diamond crossing.  They work perfectly without any hesitation and solved what I thought was going to be a bit of a problem - wiring up a simple two-road junction. I'm very pleased. 

Peterfgf

[Oldddudders]

Using an ordinary multimeter to test voltages on DCC is unreliable, because the DCC rails are conveying more than just traction voltage. Your frog measurements should simply be of resistance, checking the expected continuity between stock rail and frog. But the polarity does not change when the points move. As has been said above, the change is triggered when the first wheel with pickups hits the frog. Since the Gaugemaster product uses a small relay, you can hear a click as the changeover happens. I have about 20 of these and am delighted. 

[ITG]

Thanks guys, penny is dropping now. I’m using DCC Concepts ADSX turnout motor switches on the second part of the layout (upper level terminus), and instructions on those do state that it is possible that one would need to reverse the frog polarity wires connected to the DCC bus. It was that in a way that confused me, as it got me thinking maybe the Autofrogs (on first part of layout) would also be similar.

Now I belatedly appreciate that although the frog polarity task is the same for both devices, the way they do it is completely different. Hence my concern was off target.

one lives and learns.........

 

 

[BokStein]

On 30/11/2020 at 17:49, ITG said:

Hi

as a relative beginner, I’d like to check my understanding on the effect of using Gaugemaster autofrogs with motorised Peco live frog points. Logic suggest to me that if using a multimeter on these points, I should see an indication of DCC voltage between the outer rail of the point, and the frog section, only in the direction the turnout is set to. And conversely, no voltage on the other rail exit? And of course vice versa when the turnout direction is changed.

 

Its not that I have a particular problem with locos negotiating points (apart from one - see below), but on checking the one troublesome one, it then led to me checking others, and I’m not getting the results I might have expected. What would you expect to see? (Note that turnouts are modified by snipping the link underneath, and using IRJs on the two frog exit rails).
 

That then leads me to wonder if the terminals on the autofrog device have a right/wrong way round ( ie a +ve and a -ve) or doesn’t it matter?

 

Incidentally, one turnout, when switched to ‘turn’ is a problem for one loco - a class 08 shunter,, so a short wheelbase. It stalls at slow speed. No other loco does, and the Class 08 is fine on other points. I’m not unduly concerned as it’s highly unlikely that the Class 08 will actually venture over that point. But this particular turnout is one of those that does not give me the readings I expected.

thanks for any help.

Ian

 

DCC has an asymmetric wave form and, as such, has no polarity. If using a voltmeter to check its presence, use an AC range.