Siemens es7138-6ba01-0ba0

By Abdullah Zahid
13 min read
Siemens 6ES7138-6BA01-0BA0 TM PosInput 1 ET 200SP technology module for RS-422 and SSI encoder position decoding in industrial automation

Siemens 6ES7138-6BA01-0BA0 TM PosInput 1 Position Decoder Module — Complete Specifications and Selection Guide

Controls engineers specifying encoder feedback into an ET 200SP distributed I/O system are often choosing between the correct technology module and an expensive integration workaround. The Siemens 6ES7138-6BA01-0BA0 — officially designated the SIMATIC ET 200SP, TM PosInput 1 counter and position decoder module for RS-422 incremental encoder or SSI absolute encoder — is a single-slot technology module that connects directly to an ET 200SP Type A0 base unit, accepts RS-422 or SSI encoder signals, and delivers resolved position or count data to the controller. It also provides 2 digital inputs and 2 digital outputs for auxiliary control signals, covering most position-sensing architectures in a single slot.

If you have already confirmed this is the right part, check current pricing and availability at LeadTime.ca — ships worldwide.

Who Should Buy the 6ES7138-6BA01-0BA0 — and Who Shouldn't

The TM PosInput 1 is the correct choice for engineers building position or speed feedback into an existing ET 200SP distributed I/O architecture. Confirm all of the following before ordering:

  • Your base unit is an ET 200SP Type A0 — not Type A1, Type B, or any other form factor
  • Your encoder outputs RS-422 incremental signals or SSI absolute encoder data — not analog, CAN, or Profibus
  • Your TIA Portal version supports firmware V2.0 (this module replaces the earlier 6ES7138-6BA00-0BA0 which ran V1.0)
  • A 24 V DC supply is available in the cabinet and your base unit power budget can accommodate the module
  • You need a single encoder input channel — applications requiring simultaneous multi-encoder inputs will need additional modules
  • Your cabinet is on the ET 200SP platform — this module is not compatible with ControlLogix, MicroLogix, or non-Siemens I/O platforms

If your encoder outputs a protocol other than RS-422 or SSI, or you are working on a non-ET 200SP platform, this module is not the right fit. Review the Siemens ET 200SP technology module family for alternatives, or contact the LeadTime.ca team for a guided selection.

On this page:

What the 6ES7138-6BA01-0BA0 Actually Does in a Real System

The TM PosInput 1 is a signal processing module, not a passive terminal block. When an RS-422 incremental encoder or SSI absolute encoder is wired to this module, the 6ES7138-6BA01-0BA0 decodes the encoder pulses or SSI serial stream, resolves the position or count value, and makes that data available to the ET 200SP controller through standard process image addressing. The controller does not need to handle pulse counting or SSI protocol decoding at the CPU level — the module handles it at the field device level, which reduces CPU scan load in high-frequency applications.

In addition to the encoder input channel, the module provides 2 digital inputs at 24 V DC and 2 digital outputs at 24 V DC. These auxiliary channels are typically used for latch signals, home position switches, enable outputs, or interlock control — functions that are directly tied to encoder-based positioning sequences. Having these built into the same module eliminates the need for a separate digital I/O base unit dedicated to one axis of position feedback. The module physically occupies a single slot in an ET 200SP Type A0 base unit, with dimensions of 7.50 x 7.00 x 2.40 cm and a weight of 0.06 kg, making it well-suited for compact automation panel builds where slot density matters.

Approximately 60 percent of distributed I/O deployments in industrial plants use modular technology modules — counters, encoders, or safety inputs — rather than fixed-function bases, and integrating encoder logic at the field level is estimated to reduce PLC CPU load by 10 to 15 percent in high-frequency scanning applications. The TM PosInput 1 is a direct expression of that architecture: intelligence at the edge, offload at the controller.

Typical System Architecture for the TM PosInput 1

The 6ES7138-6BA01-0BA0 sits in the middle of the signal chain between the physical encoder on the machine and the controller that uses position data for motion or process logic. It does not communicate directly with the PLC over a separate fieldbus — it is part of the ET 200SP node, which communicates upstream via PROFINET or PROFIBUS depending on the interface module used.

  • PLC or motion controller (upstream) communicates with the ET 200SP interface module over PROFINET or PROFIBUS
  • ET 200SP interface module distributes process data and power across the base unit backplane to all installed modules
  • 6ES7138-6BA01-0BA0 TM PosInput 1 occupies one slot in the ET 200SP Type A0 base unit, receiving 24 V DC power from the base unit rail
  • RS-422 incremental encoder or SSI absolute encoder on the machine connects to the module via shielded twisted-pair cable
  • Auxiliary 24 V DC signals (home switch, latch, enable) connect to the 2 DI and 2 DQ channels on the same module

Where Engineers Deploy This Module: Applications and Industries

The TM PosInput 1 is specified most frequently in applications where a machine requires closed-loop position feedback without the cost or panel footprint of a standalone encoder gateway. Conveyor indexing systems in food and beverage packaging plants use this module to track product position as carriers advance through filling and capping stations, with the encoder mounted on the conveyor drive shaft or a dedicated measuring wheel.

Rotary packing equipment in pharmaceutical production relies on this module for motor speed feedback and pulse counting — verifying that the rotary turret has completed the correct number of revolutions before a fill valve opens. In automotive assembly, the module supports angular position feedback for robotic joint positioning where the robot arm encoder outputs RS-422 signals that feed directly into the ET 200SP distributed I/O node mounted on the robot cell panel.

Linear displacement monitoring on hydraulic or pneumatic cylinders is another common deployment, using a linear encoder with RS-422 output to track cylinder stroke, with the TM PosInput 1 providing the decoded position value to a motion function block in the CPU. Batch counting and tally verification in production lines — counting discrete products, strokes, or actuations — rounds out the typical use cases, particularly in printing and textile machinery where encoder-based cycle counting drives quality verification logic.

Application Typical Deployment
Conveyor indexing (food and beverage packaging) RS-422 incremental encoder on drive shaft; position feedback to ET 200SP node on panel
Rotary packing equipment (pharmaceutical) Motor shaft encoder, pulse counting and speed feedback for fill cycle control
Robotic joint positioning (automotive assembly) RS-422 encoder on robot joint; TM PosInput 1 in cell-mounted ET 200SP station
Linear cylinder displacement monitoring Linear RS-422 encoder on cylinder; stroke position decoded to motion function block
Batch counting and production tally (printing, textiles) SSI or incremental encoder on main drive; count values used for quality verification logic

Purchase-Decision Specs: What You Need to Know Before Ordering

Specification Value
Model / Article Number 6ES7138-6BA01-0BA0
Official Product Name SIMATIC ET 200SP, TM PosInput 1 counter and position decoder module for RS-422 incremental encoder or SSI absolute encoder
Form Factor Single-slot technology module
Dimensions (L x W x H) 7.50 x 7.00 x 2.40 cm
Weight 0.06 kg (module only)
Compatible Base Unit ET 200SP Type A0
Power Supply Voltage 24 V DC (via base unit)
Supported Encoder Protocols RS-422 incremental encoder; SSI absolute encoder
Digital Inputs / Outputs 2 DI (24 V DC, isolated) / 2 DQ (24 V DC, open-drain compatible)
Firmware Version V2.0 (replaces 6ES7138-6BA00-0BA0 V1.0)

Full technical specifications are available on the product page at LeadTime.ca.

6ES7138-6BA01-0BA0 vs. 6ES7138-6BA00-0BA0: Which Version Do You Need?

Module Firmware Packing Unit Status Use When
6ES7138-6BA01-0BA0 V2.0 Single unit Current version New installations, replacements, and all current ET 200SP builds
6ES7138-6BA01-2BA0 V2.0 Pack of 10 Current version (volume pack) Volume orders for OEM builds or maintenance stock
6ES7138-6BA00-0BA0 V1.0 Single unit Previous version (superseded) Legacy replacement only — confirm TIA Portal version compatibility before ordering
TM Count 1 (ET 200SP) — Single unit Current Frequency or pulse counting only — no RS-422 or SSI protocol decoding required

For systems already running the 6ES7138-6BA00-0BA0, the 6ES7138-6BA01-0BA0 is a direct compatible replacement at firmware V2.0. If your architecture requires RS-422 or SSI encoder decoding, the TM PosInput 1 is the correct choice — check current availability at LeadTime.ca.

Expert Verdict: Honest Assessment and Procurement Reality

The 6ES7138-6BA01-0BA0 does exactly what it promises for engineers who are already inside the ET 200SP ecosystem. The single-slot form factor, direct integration with the Type A0 base unit backplane, and support for both RS-422 incremental and SSI absolute encoder protocols make it the most efficient way to bring encoder feedback into a distributed I/O node without adding a separate gateway, a separate power supply, or additional field wiring between devices. The inclusion of 2 DI and 2 DQ channels in the same module is a genuine time-saver in position control applications where a home switch or enable signal always travels alongside the encoder. Solid-state modules of this type typically achieve MTBF of 100,000 or more hours under rated conditions (24 V DC, 0 to 50°C ambient), and most deployments report zero field failures within 5 to 7 year system lifecycles.

The honest constraint to name is this: the module handles one encoder channel. Applications requiring simultaneous feedback from two or more encoders need multiple modules and multiple Type A0 base unit slots — or a different architecture entirely. This is not a weakness unique to this module, but it is something to account for in multi-axis systems before populating the BOM. If your encoder outputs a protocol other than RS-422 or SSI — analog voltage, CAN, Profibus encoder — this module will not work, and no amount of configuration will change that. Buyers moving to this module from a non-ET 200SP platform (Rockwell CompactLogix, Beckhoff TwinCAT, Omron NJ/NX) need to evaluate the full system cost of platform migration; the TM PosInput 1 cannot be used standalone outside the ET 200SP base unit environment.

On procurement: a single TM PosInput 1 typically ranges from 150 to 250 USD in current market conditions, depending on order volume and distributor. The pack-of-10 article number 6ES7138-6BA01-2BA0 is worth evaluating for OEM builds or maintenance stock programs. Standard lead times for single units run 2 to 4 weeks through authorized distributors; pack-of-10 units may ship from regional hubs within 1 to 2 weeks. If this matches your system requirements, view current stock and pricing at LeadTime.ca.

For volume pricing or to confirm lead time before committing to a build, contact the LeadTime.ca team directly — we ship worldwide.

Wiring and Installation: What to Verify Before You Start

  • The module must be inserted into an ET 200SP Type A0 base unit — verify the base unit part number and physical label before installation; the module will not initialize in a non-compatible base unit slot
  • RS-422 encoder wiring requires shielded twisted-pair cable with 120-ohm impedance rating; shield must be grounded at one end only (typically the module side) to avoid ground loops
  • SSI encoder connections are frequency-dependent — confirm cable length does not exceed the maximum distance specified in the module manual, as signal attenuation at high encoder frequencies causes missed pulses and counter resets
  • The 24 V DC auxiliary supply for the 2 DI and 2 DQ channels must share the same reference ground as the base unit supply to ensure correct signal levels and avoid isolation faults
  • Before applying power, verify the TIA Portal project hardware configuration recognizes the module in the correct slot and that the technology object has been configured for the correct encoder type (RS-422 incremental or SSI absolute) — mismatched configuration is the most common commissioning error

Compatible Modules and System Expansion Within ET 200SP

The 6ES7138-6BA01-0BA0 is designed to work alongside other ET 200SP modules within the same base unit assembly. The following modules are relevant for engineers building out a complete ET 200SP node that includes the TM PosInput 1:

  • ET 200SP Type A0 base units (6ES7193-6... series) — mandatory host for the TM PosInput 1; select the correct current rating and color coding for your wiring scheme
  • TM Count 1 (ET 200SP counter module) — used when pulse or frequency counting is needed without RS-422 or SSI protocol decoding; can be installed in adjacent slots on the same base unit assembly
  • ET 200SP digital input and output modules — standard 24 V DC DI/DQ modules for general I/O expansion beyond the 2 DI and 2 DQ channels provided by the TM PosInput 1
  • ET 200SP interface modules (PROFINET or PROFIBUS variants) — required upstream component that connects the entire ET 200SP node to the controller network; module selection is independent of the TM PosInput 1 but must match your fieldbus infrastructure

Wrong-Part Prevention: Pre-Order Checklist

Before submitting a purchase order for the 6ES7138-6BA01-0BA0, verify every item on this checklist. Skipping any one of these steps is the documented cause of most incorrect module orders, field returns, and commissioning delays:

  1. Confirm base unit is ET 200SP Type A0 (not Type A1, B, or other form factor)
  2. Verify encoder output is RS-422 incremental OR SSI absolute (not analog, CAN, Profibus)
  3. Check firmware version is V2.0 or compatible replacement target is V1.0 (6ES7138-6BA00-0BA0)
  4. Confirm 24 V DC supply available in cabinet and base unit power budget allows module
  5. Verify wiring length to encoder does not exceed shielded cable limits (check manual for max distance)
  6. Ensure engineering tool (TIA Portal) version is compatible with module firmware
  7. Confirm module is not already installed or double-ordered in bill of materials

If any item on this list raises uncertainty, contact the LeadTime.ca team before ordering — it is faster than returning the wrong part after delivery.

Frequently Asked Questions

Is the 6ES7138-6BA01-0BA0 a direct drop-in replacement for the 6ES7138-6BA00-0BA0?

Yes. The 6ES7138-6BA01-0BA0 at firmware V2.0 is confirmed as a direct compatible replacement for the earlier 6ES7138-6BA00-0BA0 at V1.0. Physical dimensions, base unit slot compatibility (ET 200SP Type A0), and encoder protocol support are identical. Verify your TIA Portal version supports V2.0 firmware before swapping modules in an existing installation.

Can this module accept both an RS-422 incremental encoder and an SSI absolute encoder at the same time?

No. The TM PosInput 1 provides one encoder input channel that is configured in TIA Portal as either RS-422 incremental or SSI absolute — not both simultaneously. If your application requires both encoder types in the same ET 200SP node, you need two separate TM PosInput 1 modules installed in adjacent Type A0 base unit slots.

What happens if I install the 6ES7138-6BA01-0BA0 in an ET 200SP Type A1 or Type B base unit?

The module is not compatible with Type A1 or Type B base units. Physical connector alignment and power distribution differ between base unit types in the ET 200SP family. Installation in the wrong base unit type will prevent module initialization and may result in hardware fault diagnostics at the interface module level. Always confirm the base unit part number ends with the Type A0 designation before inserting the module.

Does the TM PosInput 1 require any special TIA Portal version or license?

The module requires a TIA Portal version that supports firmware V2.0 of the 6ES7138-6BA01-0BA0. Refer to the Siemens equipment manual (published 05/2020) for the minimum TIA Portal version. No separate technology license beyond the standard TIA Portal engineering package is required for basic technology object configuration, but verify your specific TIA Portal edition supports ET 200SP technology modules before starting the project.

What is the difference between the TM PosInput 1 and the TM Count 1 module?

The TM Count 1 is a counter module — it counts pulses and measures frequency but does not decode RS-422 differential encoder signals or SSI serial position data. The 6ES7138-6BA01-0BA0 TM PosInput 1 includes the signal decoding hardware and firmware needed to interpret RS-422 phase A/B incremental encoder signals and SSI absolute position data. If your application needs closed-loop position feedback from a standard industrial encoder, the TM PosInput 1 is the correct module; if you only need to count contact closures or TTL pulses, the TM Count 1 is sufficient and typically lower cost.

What is the typical lead time for the 6ES7138-6BA01-0BA0 and can it be ordered internationally?

Standard lead times for single units run 2 to 4 weeks through authorized distributors. The pack-of-10 article number 6ES7138-6BA01-2BA0 may ship from regional distribution hubs within 1 to 2 weeks for volume orders. LeadTime.ca ships worldwide — buyers outside North America can request a quote directly through the product page or contact form.

Why Order the 6ES7138-6BA01-0BA0 from LeadTime.ca

  • LeadTime.ca ships the 6ES7138-6BA01-0BA0 worldwide — no regional restrictions on quoting or fulfillment
  • Single-unit and pack-of-10 (6ES7138-6BA01-2BA0) orders both available — useful for maintenance stock and OEM BOM builds
  • Volume pricing available on request — contact the team before committing to a large-quantity order
  • Hard-to-source ET 200SP technology modules and base units can be cross-referenced and sourced together, reducing procurement round-trips
  • Direct technical questions on compatibility and lead time answered by the team before you order

At-a-Glance Summary

  • Article number: 6ES7138-6BA01-0BA0 — SIMATIC ET 200SP, TM PosInput 1 counter and position decoder module for RS-422 incremental encoder or SSI absolute encoder
  • Single-slot technology module; dimensions 7.50 x 7.00 x 2.40 cm; weight 0.06 kg; country of origin Germany
  • Requires ET 200SP Type A0 base unit — not compatible with Type A1, Type B, or other base unit form factors
  • Accepts RS-422 incremental encoder input OR SSI absolute encoder input — one channel, configured in TIA Portal
  • Includes 2 digital inputs and 2 digital outputs at 24 V DC for auxiliary position control signals
  • Firmware V2.0 — direct compatible replacement for the earlier 6ES7138-6BA00-0BA0 at V1.0
  • Available as single unit (6ES7138-6BA01-0BA0) or pack of 10 (6ES7138-6BA01-2BA0)
  • Typical single-unit lead time 2 to 4 weeks; pack-of-10 may ship within 1 to 2 weeks from regional hubs
  • Typical price range 150 to 250 USD per unit depending on order volume and distributor
  • Solid-state module; typical MTBF 100,000 or more hours at rated conditions (24 V DC, 0 to 50°C ambient)
  • Primary industries: food and beverage packaging, pharmaceutical production, automotive assembly, machine tools, printing, textiles, material handling, robotics