Hello Sun Shine;

Based on the information available on the following documents from heidenhain (your attachments were not available), the signal from the Linear Guage acts as a TTL encoder.

EXE 600 Series - Heidenhain

Length Gauges - Heidenhain

So you need a module in the S7-300 offering that can read and interpret these signals.

An FM 350-1 (if you have only one connected encoder) or FM 350-2 (if you have more, up to 8) is able to connnect to TTL signals from an encoder; thewiring diagrams in ther manualsspeak of 5V incremental encoders. More information here:

FM 350-1 Counter Function Module Installation and Parameter Assignment

SIMATIC S7-300 FM 350-2 Counter Module

A less expensive alternative, if you have a Profibus-DP network attached to the S7-300 PLC, to use an ET 200S (IM 151-1) slave that includes a 1Count5V module. See here:

1Count 5V.

Hope this helps,

Daniel Chartier