Chapter 4 - Bench Tests; General; Testing Considerations; Bench Test With Built-In Signal Generator - TC Communications TC1540 User Manual

Rs-232/rs-422/rs-485 fiber optic modem

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Table Of Contents

Table of Contents

General

It is highly recommended to conduct bench tests before actual installation. Bench testing allows the user to

become familiar with all the functions and features of the TC1540 in a controlled environment. Knowledge

of the TC1540's functions and features will ease installation and troubleshooting efforts later on.

Testing Considerations

Most of the following bench tests specify a BERT (Bit Error Rate Tester) Test Set be used to perform the

test. You may substitute the BERT with a PC (with a terminal emulation program that matches your devices

RS-232, RS-422, or RS-485 interface) if necessary. For RS-485 interfaces, make sure the baud rate on the

BERT or PC matches the baud rate DIP switch settings (SW6, SW7 and SW8) on the units tested.

The connection diagrams in this chapter are typical for all three types of interfaces; however, the DIP switch

settings will vary depending on the type of interface, baud rate, and whether your unit is a single or dual optic

model. The loopback tests can not be performed on a TC1540 unit with a 2-wire RS-485 interface due to

its half-duplex operation; however, the Signal Generator feature can be used to facilitate troubleshooting.

The DIP switch illustrations on each unit are typical for a dual optic TC1540 with a 4-wire RS-485 interface

communicating at 9600 baud rate (Async).

Bench Test With Built-In Signal Generator

The TC1540 has a built-in signal generator to simulate a polling device's or RTU's incoming electrical signal.

The built-in signal generator is a pulse signal indicated by a blinking LED. The flash rate is intentionally

reduced for easy visual confirmation.

1. Set up the bench test as shown in Figure 14. At the local TC1540 unit, turn on the "SIGGEN" by sliding

SW3 to the Right. The "TD" LED on the local TC1540 should start blinking. Likewise, the "RD" LED

on the remote TC1540 should also blink, indicating receipt of the local unit's simulated polling message.

2. At the remote TC1540, turn on the "SIG-GEN" by sliding SW3 the Right. The "TD" LED should start

blinking. Verify that the local unit's "RD" also blinks, indicating receipt of the remote unit's simulated

response.

TxD

RxD

RS-232

Set SW3 to left

Figure 14.