S7-300 Module data
Manual, 06/2017, A5E00105505-AJ
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Signal modules
This chapter describes the technical data and properties of the S7-300 signal modules.
7.1 Module overview
Introduction
The table below summarizes the essential features of the signal modules described in this
chapter. This overview supports you in selecting a module to suit your requirements.
Table 7- 1 Special signal modules: Overview of properties
Simulator module SM 374;
IN/OUT 16
Position decoder module
SM 338; POS-INPUT
Number of in-
puts/outputs
• max. 16 inputs or outputs
1 slot reserved for non-
programmable module
• 3 inputs for absolute en-
coders (SSI)
• 2 digital inputs for freezing
encoder values
Suitable for... Simulation of:
• 16 inputs or
• 16 outputs or
• 8 inputs and 8 outputs
Dummy for:
• Interface modules
• non-programmable signal
modules
• modules which occupy 2
slots
Position detection using up to
three absolute encoders (SSI)
Encoder types: Absolute en-
coder (SSI), message frame
length 13 bits, 21 bits or 25 bits
Data formats: Gray code or
Isochronous mode
no no yes
Programmable diag-
no no no
Special features Function adjustable with
screwdriver
the mechanical structure and
addressing of the overall con-
figuration remains unchanged
when DM 370 is replaced with
SM 338 does not support ab-
solute encoders with a mon-
oflop time > 64 µs