Troubleshooting Non-Updating Digital Inputs in CFC Monitoring While Active in HW Config (ET 200SP in PCS 7 V8.1/V8.2)

In SIMATIC PCS 7 (v8.1 and v8.2) with CPU 410-5H, when digital input signal transitions are clearly visible when monitoring hardware in HW Config but fail to update inside CFC charts (reading 0 or static in test mode), the root cause is typically that an unreleased remote I/O interface module (such as ET 200SP IM 155-6 PN ST v1.1) was used instead of an officially released PCS 7 High Feature module (such as 6ES7155-6AU00-0CN0), or the peripheral address was assigned to a Process Image Partition (PIP) that is not being evaluated by the cyclic interrupt organization block executing the chart. Without an officially released module, automated module driver generation fails, causing channel drivers to passivate inputs with 'Bad = 1'.

HW Config Online Monitoring vs CFC Process Image Updating

During plant commissioning, engineers frequently encounter a perplexing discrepancy where a physical digital input LED lights up, HW Config online monitoring confirms the bit transitions to 1, but the CFC chart monitoring displays 0:
- HW Config Direct Peripheral Query (PIW:P):
* In HW Config, selecting Monitor/Modify reads the raw physical peripheral input memory directly across the PROFINET or PROFIBUS bus via low-level diagnostic calls, bypassing the CPU's process image.
- CFC Cyclic Process Image Execution:
* CFC logic does not read raw hardware peripherals directly. It reads the controller's Process Image (PI).
* For an input to update inside a CFC chart:
1. The hardware module must be parameterized in HW Config.
2. The input address must reside within an active Process Image Partition (PIP) tied to the cyclic OB executing that chart.
3. The channel driver block (Pcs7DiIn) must receive healthy module diagnostic parameters (Mode = 16#8000FFFF).
4. If any of these links is broken, the CFC process image remains static.

The Role of Released Module Catalogs in PCS 7 (PCS7_V81 / PCS7_V82)

A frequent source of commissioning failure occurs when hardware components from standard STEP 7 (TIA / Machine Building) are inserted into a PCS 7 project:
1. Unreleased Standard Modules:
- The ET 200SP Standard Interface Module (6ES7155-6AU00-0BN0 IM 155-6 PN ST Firmware V1.1) was engineered for SIMATIC S7-1500 / S7-300 standard automation.
- It was never released for SIMATIC PCS 7 V8.1 or V8.2 automated module driver generation.
2. Failure of Driver Generation:
- When CFC compiles with Generate Module Drivers, the compiler checks the hardware catalog profile.
- Because the ST module lacks the required PCS 7 diagnostic profile, the compiler skips driver generation.
- The Pcs7DiIn block's Mode parameter remains 16#00000000, causing the driver to declare the signal defective (Bad = 1, Out.ST = 16#00) and output 0 to the logic.

Process Image Partition (PIP) Alignment and Diagnostic Drivers

To ensure inputs update reliably in CFC:

Replace Unreleased Module with Released Hardware:
- In HW Config, replace the IM 155-6 PN ST with an officially certified PCS 7 interface module:
- ET 200SP IM 155-6 PN High Feature (HF) (6ES7155-6AU00-0CN0).
- In the hardware catalog, ensure the profile is selected from:
  Catalog Profile: PCS7_V82 (or PCS7_V81).
Verify Process Image Partition (PIP) Assignment:
- Double-click the digital input module in the ET 200SP rack.
- In Object Properties > Addresses, check the Process Image:
- If the CFC chart executes in OB35 (100 ms), assign the module to PIP 1 (or ensure PIP 1 is assigned to OB35 under CPU Cycle properties).
- If assigned to OB1-PI, the addresses update only during background cycles, causing severe update lag.
Re-compile CFC with Module Drivers:
- In SIMATIC Manager, select the chart folder and execute Chart > Compile > Complete Program.
- Check Generate module drivers.
- The compiler automatically links the diagnostic status of the High Feature module to the channel driver, resetting Bad to 0 and enabling real-time monitoring.

ET 200SP Module Release Status and Compatibility Table

The following table details ET 200SP interface module release status across PCS 7 versions:

ET 200SP Module DescriptionMLFB / Order NumberFirmware ReleaseReleased in PCS 7 V8.1?Released in PCS 7 V8.2?Released in PCS 7 V9.0?IM 155-6 PN Standard (ST)6ES7155-6AU00-0BN0V1.1 / V3.0NO (Unsupported)NO (Unsupported)NOIM 155-6 PN High Feature (HF)6ES7155-6AU00-0CN0V3.0 / V3.1YES (With HSP)YESYESIM 155-6 PN High Feature (HF)6ES7155-6AU01-0CN0V4.1 / V4.2NOYES (With Update)YESET 200SP HA Interface Module6ES7155-6AU00-0HA0V1.0+NONOYES (Native Flagship)

Verification

To confirm that digital inputs are updating in CFC:
1. In HW Config, verify that the module is replaced with 6ES7155-6AU00-0CN0 and shows PIP 1.
2. Open the CFC chart in test mode (Ctrl + T).
3. Observe the Pcs7DiIn block:
- Input parameter Mode must read a non-zero valid bitmask (e.g. 16#8000FFFF).
- Output Bad must read 0 (FALSE).
- Output Out.ST must read 16#80 (Good).
4. Actuate the physical field switch wired to input terminal I 3.6:
- Confirm that the terminal LED turns on.
- Confirm that Pcs7DiIn.PV_In transitions from 0 to 1 in the CFC chart immediately.
- Confirm that downstream motor logic receives the updated signal without delay.

Limitations and Operational Precautions

When selecting remote I/O for SIMATIC PCS 7:
1. Catalog Profile Selection Mandate: Always set the catalog drop-down filter in HW Config to PCS7_<Version> rather than Standard. This prevents inadvertently inserting machine-building modules that lack PCS 7 driver support.
2. PROFINET S2 System Redundancy: If connecting ET 200SP to redundant S7-400H or CPU 410-5H controllers, ensure the interface module firmware supports PROFINET System Redundancy (S2); Standard (ST) modules support only simplex communication.
3. Firmware Mismatches in HW Config: If the physical module firmware is V3.1 but configured as V1.1 in HW Config, PROFINET name resolution will succeed, but cyclic diagnostic data records will fail to initialize.

Engineer FAQ

Why did HW Config see the input when CFC did not?

HW Config reads raw peripheral addresses directly over the network via acyclic diagnostic queries. CFC reads the controller's Process Image Partition, which was not updating due to unreleased module drivers or missing PIP assignment.

Can I force the unreleased Standard (ST) module to work in CFC?

Yes, for temporary testing: manually set the Pcs7DiIn input Mode := 16#8000FFFF. This forces the driver to ignore missing diagnostic blocks and process the input. However, this bypasses all wire-break and module diagnostics and is not approved for production.

Where is the 'Generate module drivers' setting located?

In SIMATIC Manager, when you execute Chart > Compile > Complete Program, the compilation dialog features a checkbox labeled 'Generate module drivers'.

What does PIP stand for in S7-400 controllers?

PIP stands for Process Image Partition (Teilprozessabbild), which binds specific blocks of I/O addresses to cyclic interrupt organization blocks (OB30 to OB38) for synchronized updating.