Siemens 6FM1721-3AA10 Positioning Module

This positioning module drives single-axis motion for SIMATIC S5 systems. It executes point-to-point positioning with high repeatability. You can program target positions directly via STEP 5 software.

Technical Specifications

Parameter	Details
Brand	Siemens
Model	Siemens 6FM1721-3AA10
Category	Positioning Module (SIMATIC S5 Series)
Dimensions (H x W x D)	250 mm x 25 mm x 210 mm
Weight	0.65 kg
Number of Axes	1 axis
Position Data Memory	32 target positions
Position Resolution	±0.01 mm (depends on encoder)
Maximum Positioning Range	±999.99 mm
Velocity Range	0.1 to 999.9 mm/s
Internal Components	1 CPU + 1 encoder interface + 1 PCB assembly
Encoder Interface	Incremental (5V TTL, up to 100 kHz)
Output Signal	24 V DC pulse/direction for drive
Power Supply	5 V DC from backplane + external 24 V DC
Current Draw (5V)	200 mA typical
Current Draw (24V external)	150 mA typical
Built-in Energy Storage	470 µF capacitor for position retention
Digital Inputs	4 (limit switches, home, start)
Digital Outputs	2 (drive enable, position reached)
Status Indicators	5 LEDs (RUN, ERROR, LIMIT, HOME, READY)
Operating Temperature	0°C to 50°C

Detailed Feature Overview

This module stores up to 32 target positions in its local memory. Each position uses a separate velocity and acceleration profile. You can sequence these positions for automated move cycles easily.

A 470 µF capacitor retains position data during brief power interruptions. Consequently, your axis does not lose its reference after a brownout. The incremental encoder interface accepts TTL signals up to 100 kHz.

You will find four dedicated digital inputs on this module. These inputs handle limit switches, home switch, and external start commands. Two outputs provide drive enable and position confirmation signals.

Installation and Programming

Siemens 6FM1721-3AA10 fits any S5 rack slot except the CPU position. Connect the encoder cable using shielded twisted-pair wiring. Set the target positions using the STEP 5 software tool.