POINT INDICATOR STANDARD
Reminder- to prevent accidental damage please make sure the power is not connected when making or altering any of the wiring connections
The point indicator shows the direction of 4 points operated by solenoid point motors. The setting of each point is shown with 2 LEDs (intended for wiring back to a control panel). The Point Indicator has a memory which remembers the point settings whilst power is turned off. The diagram below shows the usual wiring to operate the points as dashed lines and the extra wiring for the point indicator as solid lines.
The point indicator will work with points powered from either a CDU (capacitor discharge unit) or an AC transformer.
CDU poweredpoints
The red and blue lines show the standard wiring to operate points with a CDU. The orange lines show the extra wiring to the point indicator board. The points must be wired so that the common connection to the point motors is made from the negative side of the CDU. The positive connection from the CDU is connected to the point motor from the switches. See diagram below. The reason for this is because the point indicator board senses positive pulses from the switch to the point motor. The point indicator will work with any supply from 12 volts to 24volts. The supply may be either AC or DC.
The connections to power the point indicator must be made from the negative terminal of the CDU to the "-" terminal of the point indicator. The other connection is made from the input side of the CDU. It is the “IN+” terminal on our CDU board. On other manufacturers boards it is the terminal which is not directly connected to the negative terminal of the output side of the CDU.
(this terminal can be found by trial and error as no LEDs will light on the point indicator unless the correct terminal is connected.)
The top 2 point motors in the diagram are shown wired as "peco" point motors, these have 4 connections. The bottom 2 are "SEEP" which have a common connection in the centre of the point motor.
The terminals are marked on the solder side of the point indicator board
WARNINGBe very careful to connect the wires from the point motor switches to the correct terminals. If they are connected to the LED terminals by mistake the board will be damaged.
AC powered points
If the point motors are powered from an AC supply without a CDU the point indicator may need a separate power supply for reliable operation.
The diagram shows how to power both the point motors and point indicators from the same supply. The AC terminal which is the “common” of the point motors must also connect to the “-“ power terminal on the point indicator.
If a separate supply is necessary for reliable operation the connections are shown below.
The terminal of the point motors supply which connects directly to the point motor also needs a connection making to the "-" terminal of the point indicator.
Powering several Point Indicators
LED wiring
The point indicator is supplied with red and green leds fitted in there operating positions. It is best to first wire up the point motor switches to the Point Indicator. Then check everything is working ok. Then wire the leds to the control panel. This order of wiring should help with tracing mistakes
The point indicator uses the fact that leds only light when the current passes in one direction. The terminals are in pairs. Current either flows from L1A to L1B or fromL1B to L1A.
The direction the current flows through the led is shown by the led having a long and a short leg. Connect short leg of green led to long leg of red led. And connect short leg of red led to long leg of green led.
It is possible to connect an extra pair of LEDs to the point indicator. The diagram below shows how the LEDs are wired. Note one leg of the LED is a little longer than the other, this is to show the polarity of the LED. (LEDs only light if the current flows in the correct direction)
The diagram below shows how to wire two LEDs to light for one point position and 2 LEDs to light for the other point position
The diagram shows how to wire bicolour 2 leg LEDs. For one point position the LEDS will light green and red. For the other point position they will light red and green
Wiring for an LED to light for the track selected
If point is set to “A” then long leg of A will be positive, hence A will light but “B” and “C” cannot light as there short legs are positive. If point set to either B or C A will not light (long leg negative) but either B or C can light depending upon setting of second point.
False lighting of LEDs
Occasionally the following problem has occurred, when switching one point the LEDs indicating another point change. This is caused by the return currents from the point motors causing pulses to flow into other point motors due to the size of the currents and resistance of the wire. The cure is to run separate returns from each point motor common back to the point motor power supply/CDU.
Step by Step Wiring Instructions
1Leave in LEDs – very important to save confusion.
2Connect power to CDU and board and check LED lights. If not you have made a mistake.
3Connect – (negative) from CDU to all point motors.
4Connect + (positive)from CDU to point motors via switches. Check each point changes.
5Connect extra wires from switches to Point Indicator boards. Check LEDs change when points are switched. If not check this wiring.
6Methodically extend each pair of LEDs to the control panel and check each works by switching the points.
Heathcote Electronics, 1 Haydock Close, Cheadle, Staffordshire ST10 1UE
Tel/Fax 01538 756800
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