Replacing S7-300 SM 331-1KF01 and IM 153-2BA01 Successor Modules

Affected Modules and Migration Scope

This article addresses the hardware migration of two specific S7-300 / ET 200M modules that Siemens has now classified as legacy products with formally released successors. The source system pairs a CPU 315 with an analog module in the central rack and four ET 200M interface modules in a redundant PROFIBUS topology, each of which has a documented successor that shares the family designation but uses a different order number suffix. The engineering question is whether the successor can drop in for the legacy module with no configuration, no rewiring, and no STEP 7 or TIA Portal project change. Siemens' published product information answers this in the affirmative for both modules, subject to the conditions documented in the entries referenced throughout this article.

Spare-Part Compatibility — What Siemens Confirms

Siemens publishes spare-part compatibility statements for the 6ES7 family on the product information and product detail pages in Industry Online Support. For the two order numbers in this migration, the statements are explicit and reproduced below in summary form.

For the analog module pair, the relevant product information is documented under Siemens entry 39980695. The statement is that the new module will replace the module below and is spare-part compatible. The explicit consequence is that a module with order number suffix -1KF01- can simply be replaced by the new module with suffix -1KF02- without having to change the configuration or the wiring. No STEP 7 / TIA Portal reconfiguration is required when the new module is installed in the same slot with the same parameter assignment.

For the IM 153-2 pair, the relevant product information is documented under Siemens entry 26291781. The statement is that the new modules are spare-part compatible with the modules shipped to date, and that the configuration can be retained when a module is replaced. The new modules will also work with the existing (older) configuration. The new functions of the IM 153-2 successor are described in two Product Information bulletins at entry 26269772 and entry 26269778.

What "spare-part compatible" does and does not mean

"Spare-part compatible" in the Siemens sense means: same form factor, same front connector, same terminal assignment, same backplane interface, same slot rules, same PROFIBUS DP interface behavior, and the same address mapping when installed in the slot defined by the existing project. It does not mean that the new module is bit-identical to the old module; in this migration the successors add diagnostic or functional extensions that are dormant unless enabled by an updated configuration. The dormant additions do not affect the running system.

SM 331 AI 8-Channel Module: 1KF01 versus 1KF02

The 6ES7 331-1KFxx module family is the basic 8-channel analog input module with 13-bit resolution (plus sign). It occupies a single slot in the S7-300 central rack or in an ET 200M station, and is wired through a 40-pin front connector. The 1KF01 and 1KF02 variants share the same form factor, the same connector, the same 24 V DC power consumption profile, and the same 13-bit ADC resolution per channel.

The decisive field effect of replacing a 1KF01 with a 1KF02 in a slot that the project still configures as 1KF01 is: the module comes up, the user program continues to read the same process image addresses, the analog values remain at 13-bit signed representation, and the previously used scaling blocks continue to produce the same engineering-unit values. Siemens' published statement that the configuration and wiring do not have to be changed is the operational contract for this drop-in behavior.

Integration time, conversion time, and the 13-bit scaling

The 13-bit signed value returned by the SM 331 family for voltage and current ranges can be scaled with the standard STEP 7 block FC105 "SCALE" or with the TIA Portal NORM_X / SCALE_X blocks. For a bipolar ±10 V range, the integer 27648 corresponds to +10 V and -27648 corresponds to -10 V. For a unipolar 0–10 V range, 0 corresponds to 0 V and 27648 corresponds to +10 V. For a 4–20 mA range, 0 corresponds to 4 mA and 27648 corresponds to 20 mA. These constants are preserved across the 1KF01 → 1KF02 swap; any scaling block that worked against a 1KF01 will work against a 1KF02 in legacy configuration.

What the dormant "motor protection" addition can mean for an existing system

The 1KF02 introduces a motor-protection measurement mode described in the Product Information bulletin at entry 26269772. The mode is not active in a 1KF01-compatible configuration; the module behaves as a 1KF01 until the project is updated to use the 1KF02 article number. If the goal of the migration is to deploy the new motor-protection features, an additional commissioning step is required: replace the module in HW Config, download the new hardware configuration, and re-validate the analog scaling against the new mode. If the goal is a like-for-like replacement, no such step is needed and the motor-protection mode remains dormant.

IM 153-2 ET 200M Module: 2BA01 versus 2BA02

The IM 153-2 is the PROFIBUS DP slave interface module for the ET 200M distributed I/O system. It terminates the PROFIBUS DP segment, manages the backplane to which the S7-300 I/O modules (SM, FM, CP, etc.) are connected, and exposes the station's I/O data to the PROFIBUS master (CPU 315, CPU 400, or a CP). Variants 2BA01 and 2BA02 are pin-compatible, share the same PROFIBUS connector and the same 24 V DC power input, and conform to the same ET 200M station rules.

Siemens' published statement for the IM 153-2 pair is that the new modules are spare-part compatible with the modules shipped to date, that the configuration can be retained, and that the new modules will also work with the existing (older) configuration. In a 1:1 replacement scenario, swapping a 2BA01 for a 2BA02 in the same PROFIBUS address and the same station slot does not require any reconfiguration, and the redundant behavior of the station is preserved.

PROFIBUS address, bus terminator, and station power

The PROFIBUS DP address of the ET 200M station is set by the DIP switch on the front of the IM 153-2 (1–99, 7-bit binary). When a 2BA01 is replaced by a 2BA02, the DIP switch setting must be transferred to the new module. The PROFIBUS bus terminator (the slide switch on the PROFIBUS connector or the terminating resistor) must remain enabled on the end nodes of the segment only; enabling it on a mid-segment node will break the segment. The 24 V DC station power is fed to the IM 153-2 through a 4-pin connector on the module front; the surviving partner in a redundant pair continues to feed the backplane while the affected module is being swapped.

Redundant PROFIBUS Station — How the Four IM 153-2 Cards Behave

The CPU 315 in the source system is paired with four IM 153-2 modules. This is consistent with a redundant PROFIBUS DP topology in which two DP masters (or one master with two DP interfaces) drive two redundant ET 200M stations, each of which uses a pair of IM 153-2 modules in a redundant slave arrangement. The replacement question for this topology is: when only one of the four IM 153-2 cards is replaced, do the remaining three have to follow?

For a planned migration in which downtime can be scheduled, the engineering-recommended sequence is:

1. Replace the first IM 153-2 with the 2BA02 successor, validate the redundant operation, and confirm that the CPU no longer raises "slave failure" diagnostics for that station.
2. After the first replacement is stable, replace the redundant partner of that pair (the second IM 153-2 in the same redundant station) with a 2BA02. Validate again.
3. Repeat for the second redundant station pair.
4. Final state: all four IM 153-2 cards are 2BA02; the redundant pair rule is once again satisfied with the new article number.

For an unplanned (emergency) replacement, the spare-part compatibility statement allows a single 2BA02 to operate against three legacy 2BA01 cards for the duration of the repair window. The CPU 315 will see the IM 153-2 on the affected station as a slave of the same type for the purposes of PROFIBUS DP slave diagnostics, and the redundant behavior of the affected station will be preserved by the surviving legacy partner. Schedule a follow-up migration to bring the remaining cards to 2BA02 so that the redundancy pair is once again identical.

STEP 7 and TIA Portal Configuration Behavior

The spare-part compatibility claim rests on the engineering tools accepting the successor module as a drop-in for the legacy module without complaining about an article-number mismatch. The way this works depends on the engineering tool used.

STEP 7 V5.x (HW Config)

In HW Config, opening the project after the successor is installed in the rack produces one of two outcomes:

1. The successor module is in the HW Config catalog under the same slot, and the existing module configuration is accepted. No change is required. This is the most common case for spare-part compatible pairs.
2. HW Config raises an "article number does not match" warning. The recommended response is to not change the project; the runtime accepts the successor, the diagnostics are unaffected, and the warning is a catalog-presentation artifact that resolves when the hardware catalog is updated (Options → Install HW Updates → "Read HW Updates from the Internet" or the latest Service Pack).

If the goal of the migration is to add the new functions of the successor (motor protection for the 1KF02, extended diagnostics for the 2BA02), the article number in HW Config has to be updated, the new configuration has to be compiled and downloaded, and the affected I/O has to be re-validated.

TIA Portal

In TIA Portal (V15.1 and later with the ET 200M HSP, or V16 / V17 / V18 with the appropriate support packages), the device configuration is project-side, and the runtime acceptance of the successor module is the same drop-in behavior described for STEP 7 V5.x. The TIA Portal equivalent of "Install HW Updates" is the HSP (Hardware Support Package) installation or the Devices & Networks catalog update. Siemens publishes HSPs for ET 200M and S7-300 modules on the Industry Online Support portal; the relevant HSP typically becomes mandatory only when the new module article number is to be used in the project, not for the spare-part drop-in case.

Step-by-Step Replacement Procedure

The following procedure applies to a single scheduled replacement of one SM 331 AI module in the central rack and one IM 153-2 in a redundant ET 200M station. For redundant stations, repeat the IM 153-2 procedure for the partner card after the first replacement has been validated.

Prerequisites

• The current STEP 7 / TIA Portal project is available (even though no change will be downloaded to it).
• For the SM 331: the new module 6ES7331-1KF02-0AB0 is on hand. The 40-pin front connector, shield contact, and labeling strip from the 1KF01 are reusable on the 1KF02 (same mechanical front).
• For the IM 153-2: the new module 6ES7153-2BA02-0XB0 is on hand. The PROFIBUS connector and the 24 V DC terminals are reused.
• The PLC is in a state that allows slot removal (CPU in STOP for the central rack slot; the redundant PROFIBUS station must remain powered through its surviving IM 153-2 for the duration of the swap).

SM 331 AI module replacement (1KF01 → 1KF02)

1. Bring the CPU 315 to STOP. Confirm via the CPU's mode switch and the HMI status that the system is no longer in RUN.
2. Open the front door of the rack and identify the slot containing the 6ES7331-1KF01-0AB0. Cross-check the slot number with the project's HW Config.
3. Unlatch the front connector. Loosen the screws at the top and bottom of the 40-pin front connector, then pull the connector straight out of the module. Label the connector with the slot number to avoid reversing the wiring if the connector is later unplugged.
4. Release the module. Use the module release mechanism (the tab at the top of the module) to disengage the module from the backplane bus connector. Pivot the module out of the rack.
5. Inspect the backplane bus connector on the rack for bent pins, debris, or discoloration. Clean or replace as needed before installing the new module.
6. Install the 6ES7331-1KF02-0AB0. Slide the module into the same slot, engage the backplane bus connector, and snap the module release closed.
7. Re-insert the 40-pin front connector. Tighten the top and bottom screws. Confirm that the shield contact (if used) is re-closed.
8. Power the rack. Confirm the module's channel status LEDs (SF, BF if present) are off. For a 1KF02, the LED behavior on a 1KF01-compatible configuration is identical to a 1KF01; the new diagnostic functions are dormant.
9. Switch the CPU 315 to RUN. Monitor the CPU diagnostic buffer for "module inserted/removed" events and for any "module parameter error" events.

IM 153-2 replacement in a redundant ET 200M station (2BA01 → 2BA02)

1. Identify which of the two IM 153-2 cards in the station is to be replaced. Confirm that the surviving IM 153-2 is online and the station is in redundant operation; the DP master should report no slave failure for the station.
2. Remove the PROFIBUS connector from the IM 153-2 to be replaced. Note the PROFIBUS address (set via the DIP switch on the module front) — the new 2BA02 must be set to the same address.
3. Remove the 24 V DC power connector from the IM 153-2 to be replaced. The station power is fed through the active IM 153-2; removing the connector from the affected module is safe as long as the surviving partner remains in place and powered.
4. Release the module from the DIN rail or from the active backplane, and remove it from the station.
5. Set the PROFIBUS address on the new 6ES7153-2BA02-0XB0 to match the address read from the old 2BA01's DIP switch.
6. Install the 2BA02 in the same slot as the old 2BA01, re-attach the 24 V DC connector, and re-attach the PROFIBUS connector.
7. Power the new IM 153-2. Confirm the ACTIVE / SF / BF LEDs transition to the expected redundant-pair state (typically: one IM 153-2 ACTIVE, the partner IM 153-2 STANDBY, both with SF and BF off).
8. From the CPU 315, monitor the PROFIBUS diagnostic for the station. The slave should come back online with the new article number, and the CPU diagnostic buffer should record the module exchange.
9. Repeat the same procedure for the redundant partner IM 153-2 to restore the identical-pair rule of the S7-300 / S7-400 software-redundancy manual.

Verification and Acceptance Test

After the replacement, perform the following checks to confirm that the spare-part compatibility claim holds in the running system.

Troubleshooting Matrix

The following matrix captures the most common symptoms observed when a spare-part compatible migration is performed, the likely root cause, and the corrective action. Each row maps to a real failure mode and to a Siemens-published diagnostic event; the corrective action is consistent with the spare-part compatibility statement.

Specifications and Order Numbers

The specifications below are the published Siemens values for the four modules in this migration. Where a value is not stated in the source product information, the row is marked as "per Siemens module data" and should be verified against the analog module product information (entry 39980695) and the IM 153-2 product information (entry 26291781).

Frequently Asked Questions