Integration and Application of Siemens SIMO-MM3 Driver Control Block in PCS7 System

Integration and Application of Siemens SIMO-MM3 Driver Control Block in PCS7 System

The Siemens Drive ES PCS7 block library is a key component used in the SIMATIC PCS7 process control system to integrate multiple drive devices. Among them, the SIMO-MM3 function block (FB621) is specifically designed to seamlessly integrate the third-generation MICROMASTER series frequency converters into the PCS7 environment, achieving centralized monitoring, operation, and maintenance of drive equipment. This article is based on the official configuration manual and systematically elaborates on the design principles, functional characteristics, configuration methods, and practical applications of the SIMO-MM3 block, providing a complete set of technical integration guidelines for automation engineers.

Overview and Integration Advantages of SIMO-MM3 Block

The SIMO-MM3 block serves as the core component of the Drive ES PCS7 library, supporting communication between the SIMATIC S7 automation system and the MICROMASTER frequency converter through PROFIBUS DP. This block not only realizes the basic start stop and speed regulation of the drive, but also deeply integrates into the architecture of PCS7, with the following advanced functions:

Multi mode operation: supports control room mode (manual/automatic), local mode, and internal/external setting value selection.

Standardization processing: Provide standardized conversion of physical quantities between set values and process values for unified monitoring interface display.

Comprehensive diagnosis: integrated drive fault reading, status monitoring, alarm and limit value monitoring functions.

Module driver compatibility: Complies with the PCS7 module driver and maintenance station concept, supports device status symbolization display and preventive maintenance.

Simulation debugging: Built in simulation interface, supporting software testing and debugging without actual hardware connection.

Detailed explanation of the core functions of the control block

1. Multi mode operation design

The SIMO-MM3 block supports flexible operation mode switching to adapt to different control scenarios:

Control room mode:

Manual/automatic selection: can be switched through the operator station (OS) or automatic program (CFC/SFC). Enter AUT-ON-OPT for operator selection and AUT-L for program control. The interlock inputs MANOP-EN and AUTOP_EN can respectively prohibit manual or automatic operation.

Internal/External Setpoints: Setpoints can be derived from internal inputs of the operator station (SP-INT) or external connections of the user program (SP.ET). Selected through SPEXT_SEL-OP (operator) or SPEXON_L (program), and can be enabled or disabled by SPIN_TEN and SPEXT-IN.

Local mode:

When the driver is controlled by a local device (such as a field button), the block enters local mode. At this point, SIMATIC stops outputting control commands but still reads the drive status. The TRACK_CW parameter allows for the selection of whether to track the manual control word when switching back to control room mode, achieving disturbance free switching.

2. Data interface and status management

The block exchanges 6 words (4 parameter words+2 process data words) of periodic data with the driver through the process data interface:

Control word (STW1): includes command bits such as ON/OFF1, OFF2 (electrical stop), OFF3 (quick stop), inverter enable, ramp function generator enable/start, set value enable, confirm, etc.

Status word (ZSW1): Output driving status, such as "Ready to Close" (QREADYON), "Ready to Run" (QOP), "Run Release" (QRUN), "Group Fault" (QGR_ERR), etc.

Process value: The main process value (such as speed/frequency) and the current process value (such as current/torque) are standardized and output.

The block defines clear driving state machines, including OFF, STOP, RUNNING, etc., and intuitively reflects them through outputs such as QOFF, QSTOP, QRUNNING, etc.

3. Standardization of set values and process values

To achieve unified display and processing, the block standardizes the physical quantities of set values and process values:

The standardized factor calculation is 16384/(FACT_SPM * FACT_CU). Among them, FACT_SPM is the reference speed (corresponding to P094 parameter), and FACT_CU is the gearbox transmission ratio.

The current process value is converted using the independent factor FACT_CPV (default 10).

In CFC, engineering units (such as Hz, rpm, A) can be allocated through I/O attributes for SP.ET, SP-INT, PV, and CPV.

4. Error response and diagnosis

The block has a comprehensive error detection and reporting mechanism:

Communication errors: including periodic communication errors (s_ERR, R_ERR), I/O access errors (PERAF), slave station failures (MODF), etc.

Parameterization error: such as zero normalization factor or LOCK_MSS parameter setting error (QPARF).

Drive fault: When the status word indicates a group fault (QGR_ERR=1), the block reads the drive's fault memory (P947) through non periodic communication, obtains the specific fault number, and displays it in the "Drive Fault" control field on the panel.

Alarm and limit monitoring: configurable upper and lower alarm limits (PVAH, PVAL) for current/torque process values, with hysteresis (HYSTERES) function. When exceeding the limit, trigger QALARM-H or QALARM-L.

5. Non periodic communication coordination

Due to the fault memory reading occupying non periodic communication channels, the block provides a coordination mechanism to prevent channel conflicts:

Input AC-START for interlock: Set 1 to indicate channel idle, block can read fault memory; Setting 0 indicates that the channel is occupied by other applications.

Output AC_SUSY indicating that the block is reading the fault memory.

When multiple blocks (such as SINAMICS G120 with incoming module and multi axis) access the same driver, AC-START must be coordinated through program logic.

Faceplate and Visualization

The SIMO-MM3 block is equipped with a feature rich PCS7 standard panel, providing an intuitive operation and monitoring interface:

Multiple control fields: The panel is divided into multiple control fields such as "automatic", "manual", "message", "drive fault", "limit value", "trend", etc., displaying the drive status from different perspectives.

Visualization of core functions:

Automatic control fields: display bar charts of set values and process values for speed/frequency, display of current process values with limits, selection of operating modes, stop commands, drive and AS status icons, simulation activation indicators, etc.

Manual Control Fields: Provides direct control for motor start stop, direction selection, stop commands, and other operations.

Driver fault field: The list displays the fault numbers and text descriptions read from the driver, and provides a "reset" button.

Limit value field: used to configure the measurement range of process values, bar graph limits, alarm thresholds and their enable states, hysteresis, and switching time monitoring parameters.

Multi language support: The panel supports five languages: German, English, French, Spanish, and Italian. Switching can be achieved by modifying the CFC block connection properties or WinCC text library.

User Objects and Icons: Provide user objects that can be embedded in flowcharts, with icon colors and directional arrows dynamically reflecting the driving status (such as green running, red fault, blue stop, etc.).

Module driver and maintenance station integration

The SIMO-MM3 block is fully integrated into the module driver/maintenance station architecture of PCS7, achieving advanced diagnostic and maintenance functions:

Module driver concept: Automatically evaluate I/O access errors, rack failures, module failures, and other events through the upstream DES-DIAG block (FB628), and pass them to the driver block. The VALUE, LADDR, DADDR and other parameters of the driver block are automatically assigned and interconnected by the module driver.

Maintenance station symbol: The driving status is passed to the standard block MOD-PAX0/MOD-PAL0 through QC and QMODE parameters, and displayed on the maintenance station with standardized symbols (such as red fault, yellow switching, green running well).

Preventive maintenance: Block integration operation hour counter, set low/medium maintenance demand time thresholds based on MAIN_L and MAIN_M parameters, and trigger corresponding levels of maintenance alarms at the maintenance station.

Simulation and debugging functions

For the convenience of project debugging and testing, the block provides complete simulation functions:

When the input SIM_SON=TRUE, the block enters analog mode and stops communicating with the real driver.

The simulation status word (SIMZSW) and process value (SIMPV, SIMCPV) are provided by external simulation blocks.

The control word (SIMSTW) and set value (SIMSP) output by the block can be read by the analog block to form a closed-loop test.

The DRVPCS7 library provides corresponding driver simulation blocks (such as those used for MICROMASTER) that can simulate the basic state machine and fault injection of drivers.

Project Implementation and Examples

The manual provides detailed installation steps and two example projects (for PROFIBUS and PROFINET respectively) to guide users to quickly get started:

Installation: Setup needs to be run on the engineering station and all OS servers/clients to install the CFC control block and WinCC panel components.

Configuration: Set the driver to DP slave in STEP 7 hardware configuration, select PCS7 message, and ensure that the I/O address starts consistently. Set the PROFIBUS address (P918) in the driver and enable remote control (P928).

Integration: Insert SIMO-MM3 block into CFC, use module driver options to automatically generate and interconnect driver chains. In WinCC, the driver panel can be integrated into the operation screen by copying user objects from the template or using the project migration tool.

Collaboration with APL library: The SIMO-MM3 block can be interconnected with motor control blocks (such as MotSpdCl FB1854) in the PCS7 Advanced Process Library (APL) through conversion blocks to achieve higher-level control strategy integration.