Basic Operation Functionality

THE PRESTO CARD converts the basic +/-12 V DC Reversing DPDT Toggle Switch operation of most Stall Switch Motors into simple, quick, manual push button or electronic digital pulse operation for each throw direction.  The digital logic and motor driver inside the card memorizes the last press or digital pulse, and always completes the throw, regardless of how short the button press duration, and then keeps the motor powered in the correct position, until a different direction is selected.


Multi-Panel Push Button Capability and Local Manual Control Disable Feature

The push button or digital pulse inputs are normally open circuit and just require simple closure to ground to make active.  Thus, they can be duplicated almost infinitely on almost any number of multiple remote panels and/or local layout positions, merely by extending and running each input wire as a bus through those desired locations. In addition, a separate LOCAL INPUT line pair with an center independently switchable ground line is provided, so that any manual buttons connected to those LOCAL INPUTS can be independently disabled. LOCAL INPUTS may be enabled simply by closing the open circuit enable line to ground or the provided ground line on the LOCAL DISABLE ground/enable line pair.

Multiple Both Single color and Bi-Color LED indicating capability

The SINGLE COLOR LED output pins are normally open circuit to Ground until enabled, so matching or summary indicator SINGLE COLOR LEDS can be placed on multiple remote panels and/or locally as well. They just each need to be powered to a positive voltage supply with a suitable current limiting series resistor. The number of LEDS duplicated per output buss line, will depend only on the total current sinking limit of the CARD (recommended max 50 mA).

The BI-COLOR LED OUTPUTS consist of two lines alternately enabled to between Ground and ~ +11 V DC.  Again these lines can be bussed through multiple locations and multiple BI-COLOR LEDS, each with its own suitable current limiting series resistor, connected ACROSS the line pair. Again, the number of LEDS duplicated per output, depends only on the total current sinking limit of the CARD (recommended max 60 mA ).

Motor and/or Multi-Motors Capability

The MOTOR and MOTOR(S) OUTPUTS consist of two lines alternately enabled to between Ground and ~ +11 V DC. A single Motor that does not have built-in current limiting resistors, may be driven from the MOTOR OUTPUT, via the appropriate resistors mounted on the PRESTO CARD. A Motor, or Multiple Motors (for crossovers, slips, etc.) that have built-in, or appropriate series resistors, per Motor, should be connected to the MOTOR(S) OUTPUT instead. The MOTOR(S)  OUTPUT can drive up to 80mA current total

Advanced Digital Electronic and Computer Driven operation capability.

All the input control signals may be activated by any normally high, high impedance, when inactive, low current, sinking to ground when active, digital output. This means that the entire functionality of the PRESTO card may be directly interfaced and controlled by nearly all popular micro-controllers or other digital electronic devices. In addition, such control may be easily mixed with manual operation to provide the maximum flexibility and convenience for practical Operations sessions.

For example the Push Buttons may be used to provide manual operation of critical main line or yard turnouts, for skilled local operators.  However, the same PRESTO controlled turnouts can be selectively disabled or completely over-ridden by a manual dispatcher, if present, or even operated partially or completely automatically by a computer operations program on those occasions when sufficient numbers of human operators are not available

The SPECIAL INPUTS allow for the PRESTO Card to be operated from other current or future option electronic devices. Current examples might include ROUTE SELECTION DIODE MATRICES, or other fixed function devices with digital outputs, such as occupancy detectors, frog powering units, etc. The SPECIAL INPUTS can also be used by programmable digital systems using micro-controllers, such as CMRI, and planned future PRESTO expanded functionality options.

Outstanding Ease of Installation and Configuration.

The electrical connections to the PRESTO card are made to industry standard, push-on, 0.1” pitch headers. Matching header connectors and even pre-formed cables are readily and inexpensively available, as they are the same as those used on the popular Arduino Microcontrollers.  

Most of the PRESTO headers are broken into mostly 2 pin pair sections, with each pair assigned to specific individual functions, and so allow for only the actually needed features to be cabled, for the lowest installation work and cost. No polarity registration is needed and all the multi-pin connections are manually reversible, both at installation configuration, and any time later. That functionality allows the power up default throw direction, the operating throw-direction, the input button/digital pulse direction and the output LEDs indications to be user selected or changed without any re-wiring or internal programming required. The power connector is specifically diode protected to prevent damage if connected in reverse. The 3 pin LOCAL INPUT Header is also reversible, as it’s ground circuit is in the center pin.

Future Feature Options Ready

Separate additional headers are included to provide the necessary low power regulated outputs for planned future micro-controller expanded functionality options.