NR NR/L3/SIG/11767/D120 ISSUE 5 PDF

INTRODUCTION

Input tenninals are not intended to be connected to voltages above 50V AC or 120V DC with respect to earth. The T121 -M Test Meter (MTM) has been designed to measure voltages at specific T121 -M frequencies. It enables readings of track circuit parameters to be taken without corruption from other track circuits or interference at non-TI21 -M frequencies, e.g. 50/60Hz. It is intended for use as an aid for setting-up and fault finding with T121 -M track circuits. For setting-up procedures please refer to the appropriate Manual/Code of Practice/Handbook.

The MTM can also be used to measure track circuit current in the running rails when used in conjunction with a suitable current transducer, e.g. LEM Flex flexible probe (not supplied with meter), please refer to the relevant T121 -M technical manual.

The code-reading version, when set to the relevant AC range and frequency, can demodulate the telegram data on a T121-M track circuit and output the result as an ASCII serial stream for use with a computer.

The meter is supplied with a carrying case and leads.