FM350-1 'Module Without Parameters' Fault S7-400 ET200S Profibus

Resolving the FM350-1 "Module is without Parameters" Fault on S7-400 ET200S Profibus

When a Siemens FM350-1 counter module (order number 6ES7 350-1AH03-0AE0) reports the diagnostic text "Module is without parameters" (German: Baugruppe ist ohne Parameter) but at the same time shows module status OK in the STEP 7 online view, the fault is almost never a hardware failure. On an S7-400 system with the FM350-1 mounted in an ET200S distributed I/O station (IM 153-1) on Profibus DP, the condition almost always traces to a mismatch between the parameter data record the CPU is sending and the parameter image the module accepts, an incompletely compiled project, an incorrect coding plug position, or a corrupted GSD/HW Config slot definition. This article consolidates the diagnostic reasoning, the complete STEP 7 recovery sequence, the hardware-side checks, and the verification procedure that resolves the fault in field commissioning.

1. Problem Statement and Symptoms

The reported fault exhibits the following signature:

• FM350-1 (6ES7 350-1AH03-0AE0) is inserted in an ET200S rack addressed by IM 153-1 on Profibus DP from a CPU 412-2 DP.
• Hardware configuration downloads to the CPU without any error or warning.
• Online Module Information shows the module status as OK.
• Diagnostic buffer or diagnostic interrupt text reads "Module is without parameters" or "Module is not parameterized".
• Counter input does not increment; FC/FB returns no valid count value (typically zero or initial value).
• No SF-LED is lit on the module in most cases, depending on the diagnostic interrupt enable state.

The combination of "OK module status" with a "module is not parameterized" diagnostic is the key clue. The slot is reachable and identified, but the parameter frame delivered by the master does not match what the FM350-1 firmware will accept. The module still answers PROFIBUS DP diagnostics, but the counter logic inside the FM350-1 has not been configured and therefore does not start.

2. System Configuration in the Reported Case

The configuration pack (HSP - Hardware Support Package) for the FM350-1 must be installed; otherwise HW Config cannot place the module in the ET200S slot and STEP 7 falls back to a default or generic module. The fault is most often triggered after a download performed with a partially compiled project.

3. How the FM350-1 Parameterization Works

The FM350-1 is a single-channel, software-parameterized counter module designed for the ET200S distributed I/O system. According to the FM 350-1 Operating Instructions, the module's operating behavior is defined entirely by the parameters transferred from the DP master during the parameterization phase of the Profibus DP startup and the configuration phase on insertion. The parameter data record contains the following main groups:

• Basic operating mode - continuous counting, single counting, periodic counting, frequency measurement, rotational speed measurement.
• Encoder interface - 24 V incremental, 24 V pulse and direction, 24 V up/down, 5 V RS422 (variant dependent).
• Signal evaluation - single, double, or quadruple evaluation of the A/B tracks.
• Hardware gate / software gate behavior, with gate function: cancel, interrupt, or freeze count on gate edge.
• Comparator thresholds, hysteresis, and output assignment (digital output modules via ET200S backplane bus).
• Diagnostic interrupts enable bits for sensor, hardware, and parameter errors.
• Substitute value behavior on CPU STOP.

Until all required parameters are correctly received and the parameter CRC inside the module is consistent, the module leaves the "not parameterized" state in its diagnostic data record 0 / 1 (byte 0, bit 4). The module still answers PROFIBUS DP diagnostics and the slot is "OK" from the master's point of view, but the count value register and the FC/FB interface return zero or undefined values.

Reference: FM 350-1 Counter Module - Operating Instructions (Siemens Support, PDF).

4. Diagnostic Data Record 0 / 1 Interpretation

When the module reports "Module is without parameters" the diagnostic data record 0 (per the FM 350-1 manual) contains the following relevant bits:

If bit 5 is set in addition to bit 4, the parameter frame is present but contains an illegal combination (e.g. encoder type 5 V RS422 on a 24 V variant of the FM350-1). If only bit 4 is set, the parameter frame has not been delivered at all - the typical symptom of a STEP 7 project-consistency or GSD slot problem.

5. Root Cause Analysis

Across all reported cases on S7-400 + ET200S, the fault is produced by one of the following five root causes, listed in order of frequency:

5.1 Incomplete STEP 7 project compile (most common)

HW Config is saved and downloaded, but the user program (Blocks) is not recompiled. The DB/UDT generated for the FM350-1 channel does not match the parameter assignment defined in HW Config, or the FC parameter block still references the old UDT. At startup, the CPU writes the parameter frame expected by the old DB while the FM350-1 expects the new layout. The "OK module status" appears because the module correctly receives a Profibus DP parameter frame - it is just not the right one.

5.2 NetPro / Profibus topology not compiled after HW change

After modifying the ET200S station, HW Config is recompiled but the Profibus network view in NetPro is not. The master system in NetPro still has the old slave configuration, and the CPU may be sending the previous parameterization record to the new module slot.

5.3 Coding plug in wrong position

ET200S modules use a mechanical coding plug on the lower side of the terminal block to enforce the terminal assignment. If the coding plug is removed or set to a position not matching the FM350-1, the module may detect a parameter assignment error and refuse the parameter frame, while the slot still appears OK to the master. The SF-LED lights if the wrong coding is detected by the firmware, but the diagnostic buffer may still show "not parameterized" first.

5.4 GSD / module substitution mismatch

If the FM350-1 was placed in HW Config as a generic or earlier firmware version than the physically installed module (6ES7 350-1AH03-0AE0), the parameter layout differs. The module detects unknown parameters and rejects them. The same effect occurs if "Replace module" was used and the order number was not updated to the latest variant.

5.5 Configuration pack (HSP) missing or wrong version

Without the proper HSP installed under STEP 7, the FM350-1 may be placed with a fallback parameter record that does not include the channel-specific settings (gate, comparator, encoder evaluation). The module rejects the partial record and reports "not parameterized".

6. Resolution: Step-by-Step Procedure

Apply the following sequence in the order given. Test the counter after each block of changes; in most cases the fault clears after step 4.

Step 1 - Verify installed configuration packs

1. In STEP 7, open HW Config.
2. From the menu, select Options > Install HW Updates (or, in older versions, Options > Install GSD files).
3. Confirm the FM350-1 (6ES7 350-1AH03-0AE0), the IM 153-1 variant, the AI RTD, and the DO module are all listed without warning symbols.
4. If any module is marked "unknown" or shows a yellow icon, install the matching HSP for the current STEP 7 version (V5.5 / V5.6 / V5.7) from the Siemens support portal.

Step 2 - Recompile the hardware configuration

1. Open the SIMATIC 300 / ET200S station containing the FM350-1.
2. Open the FM350-1 slot and review the "Properties" dialog. Verify:

• Encoder type matches the Hubner OG9 D 1024 (24 V incremental, 1024 ppr, A/B with index).
• Signal evaluation is set to "double" or "quadruple" as required by the application.
• Hardware gate is enabled if the wiring uses the HW gate input.
• Diagnostic interrupts are enabled if you want bit 4 of DS0 to be raised.
• Substitute value on STOP matches the application requirement.

3. From the menu, select Station > Save and Compile.
4. Close the station and return to the project view.

Step 3 - Recompile the Profibus network in NetPro

1. Open NetPro by selecting the project node and pressing the NetPro button or via Options > Configure Network.
2. Verify that the ET200S slave appears with the correct Profibus address and that the master system symbol is intact.
3. Select Network > Save and Compile (or Network > Compile in some versions). The system data (SDB) are regenerated.
4. If NetPro prompts that the network is inconsistent, follow the prompts to resolve the inconsistency before continuing.

Step 4 - Recompile the entire STEP 7 program

1. In the project view, right-click the Blocks container of the S7-400 CPU.
2. Select Check Block Consistency... and resolve any reported inconsistencies.
3. Open the menu Program > Compile All (or Program > Compile (All)). This regenerates the FM350-1 instance DB / UDT.
4. Confirm that the UDT for the FM350-1 channel contains all of the expected elements: LOAD_VAL, ACT_CNT, SETPOINT, COMPARATOR, STATUS, ERR, etc. Missing or renamed elements indicate a stale project.

Step 5 - Save project with reorganization

1. Select File > Save As....
2. Tick the option Save with reorganization (slow).
3. Save the project to a new name or overwrite the existing one.

This forces STEP 7 to rebuild the project database and often eliminates the residual inconsistency that produces the "not parameterized" condition.

Step 6 - Re-download to the CPU

1. Select the Blocks container and the System Data container of the CPU.
2. Download both to the target (right-click > Download). The download order does not matter if the project is consistent.
3. Confirm that the CPU goes through a restart (STOP > RUN) and that no SF-LED is lit on the FM350-1.

Step 7 - Verify the FM350-1 online

1. In HW Config, right-click the FM350-1 slot and select Module Information.
2. Open the Diagnostics tab. The "Module is without parameters" message must be gone.
3. Open the I/O tab. Set the load value and the gate. The actual count value should follow the encoder pulses.

7. Hardware-Side Checks

7.1 Coding plug verification

The ET200S coding plug is a small plastic key inserted into the terminal block. It must match the FM350-1 terminal block type (TB30 / TB30R for the FM350-1). Procedure:

1. Power down the ET200S station.
2. Remove the terminal block from the FM350-1 module.
3. Check the position of the coding plug on the underside of the terminal block.
4. Compare with the position shown in the FM 350-1 operating instructions, section "Terminal assignment".
5. If the coding plug is missing or in the wrong position, install the correct one (each FM350-1 is shipped with a coding plug; spare parts are 6ES7 193-4CE00-0AA0 family).
6. Re-insert the terminal block and power the station back up.

7.2 Encoder wiring verification

For the Hubner OG9 D 1024 in 24 V HTL operation on the FM350-1 24 V variant:

Always confirm against the Hubner OG9 D 1024 data sheet; the exact wire color assignment depends on the cable variant ordered with the encoder.

7.3 Module substitution test

Swap the suspect FM350-1 with the FM350-1 from the second process line that is operating correctly. If the fault follows the module, the module is faulty. If the fault stays with the slot, the issue is in the parameterization and the project, not the hardware. This test isolates the failure to one side of the Profibus DP parameter handshake.

8. Parameter Assignment Reference

9. Parameterization State Machine

If the parameter CRC inside the FM350-1 does not validate, the module stays in the "not parameterized" state and reports bit 4 in DS0. The master sees the slot as OK because the module still answers PROFIBUS DP correctly - only the diagnostic data carries the parameterization error.

10. Verification Procedure

1. In STEP 7 online view, open the FM350-1 instance DB.
2. Confirm that the ACT_CNT tag increments when the encoder shaft is rotated.
3. Trigger a controlled rotation of 1024 pulses (one mechanical revolution) and confirm that ACT_CNT changes by 1024 (single), 2048 (double) or 4096 (quadruple) - matching the signal evaluation selected in HW Config.
4. Open Module Information > Diagnostics and confirm no diagnostic entries are present.
5. Cycle power on the ET200S station. The module must come up parameterized without operator intervention.
6. Cycle power on the CPU. The CPU must restart, parametrize the FM350-1, and resume counting.

11. Field Commissioning Checklist

• [ ] HSP for FM350-1 6ES7 350-1AH03-0AE0 installed in current STEP 7 version.
• [ ] HSP for IM 153-1 (6ES7 153-1AA03-0XB0 or actual variant) installed.
• [ ] Coding plug on terminal block matches FM350-1.
• [ ] HW Config compiled and saved.
• [ ] NetPro network compiled.
• [ ] "Check Block Consistency" executed with no errors.
• [ ] "Compile All" executed on the S7 program.
• [ ] "Save with reorganization" executed.
• [ ] Blocks and System Data downloaded to CPU.
• [ ] CPU cold restart performed.
• [ ] Module Information: no "module is without parameters" diagnostic.
• [ ] Encoder count increments on shaft rotation.
• [ ] SF-LED on FM350-1 off.

12. Common Pitfalls and Edge Cases

Module reports "OK" but counts are zero: This is the same condition as the reported case. The module answers the Profibus DP diagnostic query with no fault but does not start counting. Treat it as a parameterization issue, not a hardware issue. Do not replace the FM350-1 before performing the project-consistency procedure above.

Module was just replaced with a different firmware index: A new FM350-1 (6ES7 350-1AH03-0AE0) carries the latest firmware. If the HW Config entry still points to a -1AH02- or -1AH01- variant, the parameter layout differs. Right-click the slot in HW Config, choose "Replace module...", and select the new order number; STEP 7 will copy the parameter assignment to the new module.

Two FM350-1 modules in the same ET200S: Both slots must use consistent parameter definitions. If one is parameterized and the other is not, the entire slave's parameterization can fail because the slave reports "not parameterized" at the station level. Parameterize both slots, recompile, then download.

ET200S with mixed module families: Combining 6ES7 131-1BL11-0XB0 (standard) and 6ES7 134-4JD51-0AB0 (high feature) digital/analog modules in the same rack is supported but requires that all HSPs are installed. An out-of-date HSP can corrupt the parameter image of the entire rack.

CPU STOP -> RUN transition with online block edit: Online modifications to the FM350-1 instance DB can be applied while the CPU is in RUN, but only if STEP 7 marks the project as consistent. If the user performs an online edit and then downloads hardware data only (not blocks), the parameter record sent to the module can be from the offline project while the running UDT is the edited one. Always re-download Blocks and System Data together.

DPV1 parameter assignment vs. DPV0 default: The IM 153-1 supports DPV1 read/write parameter records. If a DPV1 PC tool is connected in parallel and writes a parameter record to the FM350-1 that differs from the CPU's record, the next CPU startup will overwrite it - but if the CPU parameterization is wrong, the DPV1 tool's value will not save the situation.

13. Troubleshooting Matrix

14. Comparison with Related Function Modules

The "module is without parameters" diagnostic is structurally the same for all of these; the resolution steps differ only in the slot / HSP / UDT layout. The same STEP 7 project-consistency procedure applies to all of them.