PPI4 BLOCK SIGNALLING DC POINTS POSITION INDICATOR.
Advanced PPI with Adjustable Brightness & Simplified Wiring.
Monitors the brief positive operating voltage across points motors when they are switched.
Lights a corresponding led on a control panel to show the last operation of each set of points.
Saves all settings automatically to memory when the power is switched off.
Monitors up to 8 sets of points
Opto-isolated inputs accept voltages from +5V to +60V
The Points Position Indicator (PPI) monitors the brief switching voltage to either of the two coils of a points motor, and displays the last operation using coloured leds which can be mounted on a route mimic.
Manual methods to switch points include simple spring-loaded switches, push buttons, probe and stud, etc and the points coils have a common connection to the ground of the supply.
When points are driven from DCC Accessory decoders, the decoders most often provide a +12V supply to the common of the points coil, and then switch the other connections of the coils to ground to switch the points (use PPI2-DCC with these).
This PPI is designed for operation on systems where the coil common is GROUND.
The microprocessor controls the led brightness and so no resistors are required, simplifying wiring up.
Power Supply
The controller is designed for use with a DC power supply of between 10V and 25V, or an AC power supply of between 10V and 16V.
Where there is a choice, the recommended power supply is 12V DC.