scope:

Each TNP within the computer unit produces up to 63 bytes of outputs towards the field, known as control telegrams, and takes in up to 63 bytes of inputs from the field, known as indication telegrams. The data described in this document controls the following items:

(1) Transfer of telegrams between the TNPs and the various items of field equipment.

(2) Configuration of TDM links.

(3) Reporting of status of TDMs and field equipment to ISM.

(4) Update of internal TNP information from master to standby computer unit.

The conversion of information between the IECC format and that of the telegrams, and other functions local to the TNP, are controlled by TNP data. TNP data is similar to SSI data and prepared in the same way. SSI data is described in the SSI Applications Manual, and the preparation of the "SSI-like" data to be used in TNPs is described in the SSI-Like Data Preparation Guides.

This document is a tutorial. No attempt is made to define the syntax of the files themselves. Instead, a higher-level description is given of the type of information which is required, and this is illustrated by examples.