BASIC APPLICATION GUIDELINES & PROGRAMMING
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5-1
SIG-00-22-02 JUNE 2022 (Revised September 2022)
Version: B.1
SECTION 5
BASIC APPLICATION GUIDELINES & PROGRAMMING
5
BASIC APPLICATION GUIDELINES AND PROGRAMMING
5.1
Introduction and Overview
The PSO Module has many features:
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Vital processor based
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Many PSO frequencies (standard and alternate) are provided
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Provides internal logging of PSO Module operation
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Programmed via the Display Module
Menus provide field selectable options such as:
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PSO transmitter, receiver, and island frequencies
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PSO transmit power
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Up to five unique modulation address codes as well as Dynamic Addressing
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Configurable inputs and outputs for an application
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Configurable receiver, island, and input pickup delays
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Drop Delay Timer, Internal Directional Stick Logic, and Stick Cancel Timer when
configured as a Crossing unit
•
Taking units Out of Service
Section 8.3.2.1 describes PSO the front panel indications for the PSO module.
The PSO Module is functionally compatible with the PSO 4000 Module, the PSO III receiver and
transmitter as well as the PSO II and PSO+ receiver and PSO II and PSO+ transmitter when
using an A or C address.
The Transmitter generates a modulated audio-frequency track signal. It sends a coded, 8-bit
address code through the rails using an audio frequency signal as a carrier. The rail
connections for the coupling unit delimit the other end of the track circuit. The modulated signal
is detected by the receiver where it is decoded and processed. The Receiver responds only to
signals of the proper frequency, address, and amplitude. The ability of the PSO Module to
differentiate between its operating signal and all other signals present on the track is due to the
nonsymmetrical coded modulation and receiver decoding techniques which ensure that the
system is immune to most foreign AM, FM, and beat signals. The receiver decodes the signal
and, if it qualifies the signal as valid, the receiver produces an output to energize a vital relay.
The receiver is connected to the track via a Tuned Receiver Coupler, which is a separate piece
of equipment.
No insulated joints are needed to confine the signal because the coupling units have low
impedance at the operating frequency of the track circuit, and high impedance at all other
frequencies. The PSO Module can also be used on the same track used for coded or non-coded
DC or AC track circuits, Grade Crossing Predictors (GCPs), motion detectors, and other audio
frequency track circuits.
The PSO Module’s crossing functionality includes two receivers plus a combination
transmitter/receiver Island Track Circuit that is incorporated into the Module. In a crossing