Sunday, October 4, 2020

Sparks Yard rebuild - general update # 2

The work on the rebuilding of the lower staging yard, also known as Sparks is entering it's second month. All of the track work has now been completed.  The turnout motors have been installed, wired and tested for correct connections to the frogs, and the control panel has been completed.

The control circuits need to be finished for that control panel to do much.  It was originally intended to reuse the Digitrax DS64 decoders but I discovered that the MP5 turnout motors draw too much current for them so I am needing to build control circuits to replace it.  A new control circuit has now been finished for the siding that is on the return track.  This will allow momentary push button switches to control the route selection.


Below is the schematic diagram of the circuit I am working on now.   This includes the diode matrix and Set / Reset logic circuits to latch relays that control the polarity of the voltage applied to the turnout motors.  This will also allow for single push button route selection of 4 tracks in the yard.



4 comments:

  1. Im interested in the issue of the DS64 and the MP5's. I have a number of MP5's running on the older DS54 and also a friend has the MP5's running on the DS64. We just set them up as a solenoid output and set the time of the pulse to be 2 seconds. As an alternative, we also use Arduino relay boards with 8 outputs to Drive MP5's to help with boards that have low current output drivers like the SE8C. Any info would be appreciated. Brendan.

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    1. Hi Brendan, I measured 110-120ma current draw on the MP5's with 12 volts. I could not find any output rating for the DS64 other than being "limited to 2 Tortoises" which I measure about 20-30ma at 12 volts. I did not know about changing the settings on the DS64. I had considered driving relays with he DS64 outputs but as I think I had burned it out I just built this circuit. When I get this done I may go back and try to get the DS64 working or sent it back to Digitrax then I can experiment with trying these other methods.

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  2. I think the main issue with 2 tortoise is that constant current for a tortoise as they are always on and taking current. If you wire the MP5 like a snap coil machine with a common and set the DS64 to drive a snap coil and set the time to 2 seconds then you wont have any issues.

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    1. Thank you Brendan for that suggestion. Assuming that the DS64 is not burned out, I am going to experiment with on the bench. Another complication in my setup is that while I replaced the Tortoises on one end of the yard, I am still using them on the other end and they are wired in pairs. So each output was driving 1 MP5 and 1 Tortoise.

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