How to Access and Configure the MPC Configurator in SIMATIC PCS 7 V9.1 SP2

In SIMATIC PCS 7 V9.1 SP2, you access the Model Predictive Control (MPC) Configurator directly from the CFC editor by right-clicking an instantiated ModPreCon block and selecting the special configuration assistant, or by launching the standalone MPC Configurator utility from the S7APC directory. The tool enables process engineers to define multivariable interactions, import step-test identification data, design Kalman filter state estimators, and calculate controller matrix parameters before downloading predictive algorithms into S7-400 or CPU 410 controllers.

Architecture of Advanced Process Control and ModPreCon in PCS 7

In complex continuous process units (such as distillation columns, multi-zone furnaces, and reactor feeds), strong cross-coupling between manipulated variables (MV) and controlled variables (CV) limits the performance of classical single-loop PID cascades.

To overcome loop interaction and dead time, SIMATIC PCS 7 integrates Model Predictive Control (MPC) through the Advanced Process Control (APC) library:
* The ModPreCon Block: Instantiated in a CFC chart executing in a cyclic interrupt organization block (typically OB32 at 1.0 s or OB35 at 100 ms). It controls up to 4 manipulated variables (MV) and 4 controlled variables (CV), with support for measurable disturbance variables (DV).
* The MPC10x10 Block: For larger multivariable units, this extended block handles up to 10 MVs and 10 CVs.
* The Internal State Model: The controller uses linear state-space formulations combined with quadratic programming (QP) optimization executed at each controller sampling interval within the automation station.

Methods for Accessing the MPC Configurator in PCS 7 V9.1 SP2

In PCS 7 V9.1 SP2, you can launch the MPC Configurator through two verified pathways:

Method 1: Context Menu from CFC Editor (Recommended)

Open SIMATIC Manager and navigate to your Automation Station's CFC chart folder.
Open the CFC chart containing the instantiated ModPreCon or MPC10x10 block.
Right-click the block header and select Special Assistant... (or Configure Block...).
Select MPC Configurator from the pop-up utility dialog. The configurator automatically binds to the specific block instance and reads current controller dimensions.

Method 2: Direct Execution from the Windows Installation Directory

If opening via CFC is blocked by user access controls:
1. Navigate to C:\Program Files (x86)\Siemens\STEP7\S7APC\.
2. Locate and execute MpcConfig.exe (or S7MpcConfigurator.exe).
3. Select File -> Open Project and browse to the STEP 7 project directory to attach to the relevant CFC block.

Workflow: Sizing and Configuring a 3x3 Predictive Controller

Define Variable Channels:
* Assign plant inputs to Controlled Variables (CV), target ranges, and weighting factors.
* Assign controller outputs to Manipulated Variables (MV) with high/low travel limits and rate-of-change limits.
* Assign external feed rate or ambient variations to Disturbance Variables (DV).
Execute Step Testing:
* Run manual or automated pseudo-random binary sequence (PRBS) step tests on each MV while recording CV responses into a CSV trend file.
Model Identification:
* In MPC Configurator, import the step-test data.
* Run the system identification algorithm to fit first-order plus dead-time (FOPDT) or higher-order transfer functions for each channel pair.
Controller Calculation and Validation:
* Tune closed-loop speed and penalty weights for control variance versus actuator wear.
* Simulate step disturbances in the offline simulator to confirm loop stability.
Compile and Download:
* Click Generate Controller Data. The configurator writes coefficient vectors directly into the instance data block of ModPreCon.
* Compile and download changes to the Automation Station in RUN mode.

Verification

In CFC dynamic test mode, open ModPreCon and verify that ManAct = 0 and AutAct = 1.
Apply a small setpoint step to CV1: observe that MV1, MV2, and MV3 adjust simultaneously according to decoupling model gains.
Verify on the WinCC OS faceplate that predictive horizon trends appear without communication dropouts.

Limitations and Operational Precautions

CPU Execution Load: Multivariable matrix inversions consume significant CPU compute time; verify that OB cycle times remain within safe limits under HW Config CPU properties.
Anti-Windup Constraints: Ensure physical actuator tracking inputs (MV_Trk) are connected to prevent internal model drift during manual override.
Firmware Requirements: Ensure the target controller firmware supports the floating-point math requirements of the APC library.

Engineer FAQ

Does ModPreCon require a dedicated license key in PCS 7?
Yes. Advanced Process Control functions require the SIMATIC PCS 7 APC license key installed in Automation License Manager.
Can ModPreCon handle non-linear processes?
ModPreCon operates on linear state-space models; severe non-linearities require gain scheduling or multi-model switching.
What is the maximum controller sampling time?
Sampling intervals should be 1/5 to 1/10 of the dominant process time constant.
How does the configurator handle missing step response channels?
If two variables do not interact, set their transfer function gain to zero in the configuration matrix.
Can I export the model to MATLAB?
Yes, MPC Configurator allows exporting step response models in CSV format.
What happens if an actuator hits a physical travel limit?
The QP optimizer respects MV high/low limits and redistributes control effort to unconstrained actuators.
Can disturbance variables be predicted?
DVs are feedforward variables; they must be measured in real time.
Does MPC require an OS server restart?
No, MPC calculations execute strictly inside the AS controller logic.
Can I edit matrix parameters online without stopping the CPU?
Yes, parameter updates can be transferred via instance DB download in RUN mode.
What is the recommended CFC runtime group for ModPreCon?
Assign the block to a dedicated cyclic interrupt OB (e.g., OB32) with a fixed sampling period.

Technical References

Siemens Manual: SIMATIC Process Control System PCS 7 Advanced Process Control (A5E39172444-AA).
Siemens Industry Online Support Entry ID 109801081: Model Predictive Control in SIMATIC PCS 7.
ISA-77 Standard for Industrial Process Control Dynamics.