Add-on Circuit for the PSX-AR
Don Fiehmann has submitted instructions for adding push button switches to control the automatic stationary decoder function of the DCC Specialties PSX-AR and more!
PSX-AR “Double Reverse Mode” CVs
The PSX-AR reverser/circuit breaker has become a very popular way to control polarity in reverse loops and wyes. With the flexible power settings it is usable on Z to G scale layouts. The PSX-AR also has many features that can be used when wired to a layout. Here are a few things that can be easily added that were not in the original instructions. There are three ideas in this article.
- Add pushbuttons to control turnout position.
- LED indication of turnout position for layout display.
- Make the reverse/short LED show only the short indication.
Pushbutton Control of Turnout
On my layout I have two PSX-ARs, one at each end of the layout. On the east end the direction through the loop is set automatically by a spring switch. On the west end the direction is set with a switch using a Tortoise controlled by the PSX-AR. The normal setting puts you into the loop in a clockwise direction. The clockwise direction is needed due to the way the three storage tracks are setup in the loop When a train exits the loop the turnout is set to the reverse position by the PSX-AR. For the next train to enter the loop correctly the turnout needs to be set back to normal. The turnout can be controlled with an accessory command via the PSX-AR and set to normal with a cab (throttle). A red/green LED near the switch in series with the Tortoise does a good job of indicating the switch position. One of the problems is the small “operator” type cabs and throttles do not have control of accessory commands. Even with the larger cabs, it would be quicker to have a simple push-button near the switch to return it to normal. Looking over the PSX-AR instruction I did not find any options for adding push-button control. This area of the layout also has some industrial switching that uses this switch. So I needed to be able to have control of the reverse position.
My solution gave control of both positions. I like simple solutions and this one qualifies for that category. Three pieces of wire and two push-button switches is all that is required. The way this works is the pushbutton switch put a short between either of the rails of the loop and one of the rails feeding the loop. This causes the PXS-AR to instantly reverse the rail polarity and also throw the switch.
Pushbutton switches mounted on the edge of the layout make it easy to see the status of the turnout. The LED is wired in series with the Tortoise switch motor. Since the pushbutton switch will momentarily take the short circuit current you should use good quality switches.
LED Indication for Layout Map Display
There are times when you need to know which way the PSX-AR is set (reversed or normal). Here is a simple circuit that uses an LED to indicate the polarity setting of the PSX-AR. It only uses three standard parts. If you have block occupancy detection circuits the resistor value should be high enough not to trip the detector circuit. The 1K value is a starter and if you have problems you can go much higher and still get a good light from the LED. Circuit connects between a reversing section and the normal trackage.
Make the reverse/short LED show only the short indication
When you have used the PSX-AR you know that the blinking LED means the polarity of the unit is reversed. A steady light means there is a short circuit. The dual indication of fine when you a are use to it. The problem that Jim Betz had was at Bay-Rails when they were using operators that were not familiar with the dual indication. They got confused and thought the blinking LED was a short instead of the just the reversed mode. Here is a circuit filters out the blinking status and lets the short indication show.