Siemens 6ES7195-7HD10-0XA0 Retrofit-Ready Redundancy Bus Unit for ET 200M Control Systems
The Siemens 6ES7195-7HD10-0XA0 is a redundancy bus unit designed for the SIMATIC ET 200M distributed I/O station, operating within the broader S7-300 control platform. As legacy ET 200M installations approach end-of-life and Siemens transitions customers toward newer architectures, this module remains a critical spare for maintaining system redundancy in existing control cabinets. SMARTNEXMSK maintains verified stock of the 6ES7195-7HD10-0XA0 to support retrofit projects, emergency replacements, and planned system upgrades — with a 12-month warranty on every unit shipped.
Whether you are sustaining an existing redundant ET 200M rack or executing a phased migration away from discontinued hardware, this bus unit provides the electrical and mechanical interface required to maintain dual-path communication between the active and standby IM 153-2 interface modules. It is fully compatible with the standard ET 200M rail-mount backplane and integrates without firmware modification into existing STEP 7 or TIA Portal-managed projects.
Upgrade Compatibility Table
| Parameter | Details |
|---|---|
| SKU / Part Number | 6ES7195-7HD10-0XA0 |
| Compatible Platform | SIMATIC ET 200M, S7-300 |
| Module Function | Redundancy Bus Unit for dual IM 153-2 configuration |
| Backplane Interface | Standard ET 200M DIN-rail bus connector |
| Communication Compatibility | PROFIBUS DP (via IM 153-2 interface modules) |
| Installation Requirement | Mounts between two IM 153-2 modules on shared ET 200M rack |
| Replacement Recommendation | Direct drop-in for failed or degraded redundancy bus units in existing racks |
| Commissioning Note | No address reassignment required; verify DP slave address on both IM 153-2 units post-swap |
| Warranty | 12 months from shipment date |
| Origin | Germany (DE) |
Retrofit Planning for Existing Automation Systems
Retrofitting an ET 200M redundancy station requires careful coordination across multiple hardware layers. The 6ES7195-7HD10-0XA0 bus unit physically bridges two IM 153-2 interface modules — the primary and standby — allowing the PROFIBUS DP master (typically a CPU 315F-2 DP or CPU 317F-2 DP in a safety-rated S7-300 rack) to maintain uninterrupted communication even during a single-point hardware failure. Before replacing this bus unit, engineers should document the current DP slave address configured on both IM 153-2 modules and verify that the S7-300 rack power supply — commonly a PS 307 series unit — can sustain the combined current draw of the redundant station during switchover events.
Terminal wiring on the ET 200M station itself is unaffected by a bus unit swap, as the 6ES7195-7HD10-0XA0 carries only the inter-module bus signal and does not terminate field I/O. However, if the retrofit is part of a broader cabinet upgrade, engineers should audit the SM 321 digital input modules and SM 322 digital output modules installed in the same rack to confirm their firmware revisions are compatible with the target STEP 7 project version. I/O module addresses are stored in the hardware configuration (HW Config) and must match the physical slot assignments after any rack reconfiguration.
For projects migrating from PROFIBUS DP to PROFINET, the 6ES7195-7HD10-0XA0 is typically replaced as part of a full ET 200M-to-ET 200SP or ET 200MP migration. In such cases, the redundancy bus unit is decommissioned alongside the IM 153-2 modules, and the new station uses IM 155-6 PN interface modules with PROFINET-based redundancy (S2 or R1 system redundancy). Planning this migration requires updating the TIA Portal project, remapping all I/O tags, and verifying HMI screen bindings — particularly for SIMATIC HMI TP700 Comfort or TP1200 Comfort panels that reference ET 200M I/O addresses directly in WinCC Comfort variable tables.
Programming cable access is also a consideration during retrofit. If the S7-300 CPU requires an online firmware update or program download during the maintenance window, a PC Adapter USB A2 or CP 5611 PROFIBUS communication card should be staged in advance. Downloading to a running redundant system requires careful use of the Load to module function in STEP 7 to avoid triggering an unplanned CPU STOP during the transfer.
Downtime Control During System Migration
Minimizing downtime during a redundancy bus unit replacement on an active ET 200M station begins with confirming that the redundancy function is fully operational before initiating the swap. Use the STEP 7 diagnostic buffer or the S7-300 CPU online diagnostics to verify that both IM 153-2 modules are in active/standby state with no existing faults. A degraded redundancy pair — where one IM 153-2 is already offline — means the replacement must be treated as a non-redundant swap, requiring a planned process shutdown.
For a healthy redundant pair, the 6ES7195-7HD10-0XA0 can be replaced with the station powered, provided the replacement procedure follows Siemens documented hot-swap sequence: isolate the standby IM 153-2, remove the bus unit, install the new unit, reconnect the standby IM 153-2, and confirm redundancy restoration via the CPU diagnostic buffer before returning the station to full redundant operation. This approach keeps the active IM 153-2 online throughout the procedure, maintaining field I/O continuity and preserving the running PLC program logic without a CPU restart.
All units supplied by SMARTNEXMSK undergo pre-shipment functional testing and are shipped with original packaging where available. The 12-month warranty covers hardware defects identified during installation and commissioning, providing additional protection during the retrofit window.
Retrofit Support FAQ
Q: Is the 6ES7195-7HD10-0XA0 a direct replacement for all ET 200M redundancy bus units?
A: Yes. The 6ES7195-7HD10-0XA0 is the standard redundancy bus unit for ET 200M stations configured with dual IM 153-2 interface modules. It is mechanically and electrically interchangeable with units of the same part number and requires no additional configuration after installation.
Q: Do I need to modify my STEP 7 hardware configuration after replacing the bus unit?
A: No hardware configuration changes are required for a like-for-like bus unit replacement. The DP slave addresses on both IM 153-2 modules must remain unchanged. If the replacement is part of a broader rack reconfiguration, a new HW Config download may be required — plan this during a scheduled maintenance window.
Q: What pre-shipment testing does SMARTNEXMSK perform on this module?
A: Each 6ES7195-7HD10-0XA0 unit is inspected for physical integrity, connector condition, and basic electrical continuity before shipment. Units are covered by a 12-month warranty from the date of shipment, covering manufacturing defects and hardware failures under normal operating conditions.
Q: Can this bus unit be used in a migration from PROFIBUS to PROFINET?
A: The 6ES7195-7HD10-0XA0 is specific to PROFIBUS DP-based ET 200M redundancy configurations. A PROFIBUS-to-PROFINET migration requires replacing the IM 153-2 modules and the bus unit with PROFINET-compatible hardware such as the IM 155-6 PN interface module for ET 200SP or ET 200MP platforms. SMARTNEXMSK can supply both legacy PROFIBUS spares and PROFINET migration components depending on your project timeline.
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