I have a turntable that uses a stepper motor to turn the table. It takes exactly 144 pulses to turn 16 degrees. I have it so that I can run it from a PC but I want to use my NCE DCC system to control it.. I have looked at several accessory decoders but I do not see any that could do this.
Does anyone have an idea of either configuring one to do this or what it would take to build a decoder for this?
The system is actually very simple using a bipolar stepper motor and a control card. One input takes a small V+ pulse to turn the motor one step. With the gearing I have in place it takes 144 to turn 16 degrees. Very slow and smooth. Another input controls direction. Either + or - will change the direction.
Any help would be appreciated.
jentel I have a turntable that uses a stepper motor to turn the table. It takes exactly 144 pulses to turn 16 degrees. I have it so that I can run it from a PC but I want to use my NCE DCC system to control it.. I have looked at several accessory decoders but I do not see any that could do this. Does anyone have an idea of either configuring one to do this or what it would take to build a decoder for this? The system is actually very simple using a bipolar stepper motor and a control card. One input takes a small V+ pulse to turn the motor one step. With the gearing I have in place it takes 144 to turn 16 degrees. Very slow and smooth. Another input controls direction. Either + or - will change the direction. Any help would be appreciated.
You didn't state exactly how you want the accessory decoder to control it. Are you looking to have the accessory send a certain number of pulses to move it a certain distance ? Or do you want to go pulse by pulse control from your NCE ? A Digitrax DS64 can send a string of pulses (designed for controlling crossing lights) that would be primarily time based (200-3000ms adjustable pulse width), not count, in that it would send pulses when you activate it and keep sending them until you switch it off. Even at 200msec though it would take quite awhile to send 144 pulses for a 16 degree move. Give us a little more info and maybe we can come up with an idea.
Engineer Jeff NS Nut Visit my layout at: http://www.thebinks.com/trains/
i need the decoder to send the correct number of pulses when requested. I saw the Digitrax one and agree it's pulse rate is too slow. The driver for the motor is capable of a much faster rate.
In a perfect world the decoder would have the ability to adjust the pulse rate and the number of pulses.
IMO, the 'right' way to do this is build a driver circuit to supply the pulses to the stepper motor and use a DCC decoder to control that. In other words - basically the Walthers turntable with a DCC decoder sending it the commands instead of pressing the buttons on the control panel. For an input, decode several bits into the track number to rotate to. For example, using 4 outputs of a LocoIO board, you could select any of 16 possible tracks. Add another output bit and you get 32 tracks. Or 16 tracks plus a direction bit (rotate clockwise or counterclockwise). If you're not using Digitrax, any accessory decoder that has 4 outputs that can be configured for steady state (ie, stall motor drive) could supply the data. Saw a pair of NCE Switch-Its, or a Switch-8 could supply the 4 track bits, a direction bit, and 3 other outputs to do something else, liek turn on and off a light on the bridge or something.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thank you for that input. That shows me how to use an off the shelf DCC product to send a signal. I am still in the dark about what kind of circuit is needed to for converting that signal into the pulses I need. Unfortunatly I am not an electronics wiz.
How is it currently connected to your PC? Does the software on the PC provide the pulses, or is there an interface circuit involved? Is this a comemrcial product or did you make it up yourself? If it's a commercial product - who makes it? If you made it yourself, do you have a schematic? By looking at what you already have we can get a better idea of what's needed to use a DCC decoder instead of the PC.