Configuring FM 350-1 Counter Modules (6ES7350-1AH03-0AE0) in SIMATIC PCS 7 CFC

In SIMATIC PCS 7, integrating the high-speed counter module FM 350-1 (6ES7350-1AH03-0AE0) into an S7-400 automation station requires installing the dedicated FM 350-1 parameterization configuration package, configuring the counting mode in HW Config, and deploying technological function blocks in Continuous Function Chart (CFC). Because standard PCS 7 module driver generation (GEN_MOD) does not automatically generate drivers for FM 350 function modules, engineers must manually deploy the CNT_CTL1 block (FB1) from the FM_CNT_LIB library or integrate the APL CountScL block. The channel logic coordinates control commands, gate enables, and counter value read-back from peripheral memory.

FM 350-1 Counter Module Architecture and Operating Modes

The SIMATIC FM 350-1 (6ES7350-1AH03-0AE0) is a 1-channel, 32-bit high-speed counter module designed for the SIMATIC S7-300 and ET 200M distributed I/O families. Capable of counting frequencies up to 500 kHz, it interfaces with 5V incremental encoders (RS422), 24V incremental encoders, and 24V directional initiators.

The module operates in three distinct operating modes configured via its hardware properties dialog:
1. Continuous Counting: The counter counts continuously between lower and upper count limits (-2,147,483,648 to +2,147,483,647), rolling over automatically.
2. Single Counting: Counts from a parameterized start value to a defined limit value; upon reaching the limit, the internal software gate terminates counting until re-armed.
3. Periodic Counting: Automatically resets to the start value upon reaching the load limit, outputting digital pulses for batch dosing, turbine flow meters, or rotational speed calculations.

When installed in an ET 200M station connected to an S7-400 CPU (e.g., CPU 416-3 6ES7416-3ES07-0AB0), data exchange occurs across peripheral I/O memory (PIB/PQB) and diagnostic data records.

Why Standard Module Driver Generation Skips FM Modules

In SIMATIC PCS 7, the driver generator (GEN_MOD) automatically creates diagnostic and signal drivers (Pcs7DiIn, Pcs7AnIn, MOD_D1) for standard analog and digital I/O cards. However, Function Modules (FMs) such as the FM 350-1, FM 352, and FM 355 are excluded from automatic module driver generation:

Asynchronous Command Protocol: FM 350-1 requires bi-directional asynchronous handshaking across the peripheral interface (acknowledging load commands, gate controls, and zero marks). Standard driver blocks cannot handle dynamic control words.
Specialized Function Block Requirement: Data exchange requires the dedicated function block CNT_CTL1 (FB1) or FM_CNT (FB2) supplied in the FM_CNT_LIB library, which coordinates communication using system data records (SFC58/SFC59 or SFB52/SFB53).
Absence of Native APL Driver: APL does not include a direct Pcs7CntIn block for FM 350. To visualize data on APL faceplates, engineers interconnect CNT_CTL1 output values to the APL technological block CountScL (FB1806).

FM 350-1 Hardware Parameters and CFC Interface Matrix

The following table summarizes hardware configuration settings and CFC block interfaces for FM 350-1:

Configuration ParameterHW Config / Block PinParameter ValueFunction / DescriptionModule AddressModule Properties (Inputs/Outputs)e.g., 256 (PIW256 / PQW256)Base I/O address for block mappingSensor TypeParameterization Screen24V Incremental (2x)Encoder signal electrical standardCounting ModeParameterization ScreenContinuous / PeriodicOperating counting algorithmBlock Module Base AddressCNT_CTL1.MOD_ADDRW#16#100 (Hex for 256)Base hardware address in hexChannel AddressCNT_CTL1.CH_ADDRDW#16#100Peripheral channel address pointerSoftware Gate EnableCNT_CTL1.SW_GATE1 (TRUE)Software enable for counter countingActual Counter ValueCNT_CTL1.ACT_CNTVOutput (DINT)Real-time accumulated counter pulsesAPL Integration BlockCountScL (FB1806)Interconnected from ACT_CNTVScales pulses into m3, liters, or RPM

Step-by-Step Procedure to Configure FM 350-1 in PCS 7

To configure the FM 350-1 counter module in a PCS 7 S7-400 project:

Install Configuration Package and Configure HW Config:
- Install the FM 350-1 Counter Configuration Package (supplied on the module CD or SIOS entry 109780813).
- In SIMATIC Manager, open HW Config for the S7-400 station.
- In the hardware catalog, browse to SIMATIC 300 -> FM-300 -> Counter -> FM 350-1 Counter (6ES7350-1AH03-0AE0).
- Drag the module into an available slot on an ET 200M distributed I/O station.
- Double-click the module to open properties; record the assigned base I/O address (e.g., input address 256, output address 256).
- Click the Parameters button to open the dedicated parameterization interface.
- Select sensor type (e.g., 24V Initiator or Incremental Encoder), set operating mode to Periodic Counting or Continuous Counting, and configure gate behavior.
- Save, compile, and download the hardware configuration to the S7-400 CPU.
Import FM_CNT_LIB Library Blocks:
- In SIMATIC Manager, select File -> Open -> Libraries.
- Open the library named FM_CNT_LIB.
- Copy function block CNT_CTL1 (FB1), DIAG_INF (FC0), and related UDTs into your project's Master Data Library.
- Synchronize the blocks into the CPU's block folder.
Instantiate and Interconnect in CFC:
- Open a CFC chart in the S7-400 program.
- Drag CNT_CTL1 (FB1) into the chart.
- Configure input parameter MOD_ADDR with the hex equivalent of the base address (e.g., for address 256 decimal, enter 16#100).
- Set parameter CH_ADDR := 16#100.
- Connect a run enable or continuous 1 to SW_GATE to open the software counter gate.
- Insert the APL block CountScL (FB1806).
- Interconnect CNT_CTL1.ACT_CNTV (DINT) to CountScL.In (converting to REAL or scaling pulses per engineering unit).
- Execute Chart -> Compile -> Changes Only and download to the controller.

Verification

Verify counter operation in CFC:
1. Open the CFC chart online and monitor CNT_CTL1.
2. Apply pulse signals or rotate the encoder connected to the FM 350-1 front connector.
3. Verify that the module's front panel channel LED pulses and CNT_CTL1.ACT_CNTV increments or decrements steadily.
4. Toggle SW_GATE to 0; confirm that counting halts immediately, proving gate control authority.
5. Open WinCC Runtime; confirm that CountScL faceplate displays the scaled technological engineering units.

Limitations and Operational Precautions

No Automatic Driver Generation: Never rely on CFC driver generation (GEN_MOD) for FM 350; missing the manual CNT_CTL1 block results in unread peripheral data.
Isochronous Mode Limitations: If high-speed positional synchronism is required on PROFIBUS DP, the ET 200M interface module must support isochronous real-time (IRT) mode (e.g., IM 153-2 High Feature).
Commercial Accuracy Notice: Verify part numbers (6ES7350-1AH03-0AE0) and encoder power supply requirements (5V DC vs 24V DC) against Siemens technical catalog specifications.