Bonfiglioli Vectron CM-PDP Profibus DP Configuration and Debugging Guide

Bonfiglioli Vectron CM-PDP Profibus DP Communication Module Configuration and Debugging Guide

In the field of industrial automation, Profibus DP remains the preferred fieldbus for many factory automation and process control scenarios due to its high real-time performance and determinacy. Bonfiglioli has provided CM-PDP communication modules for its ACTION and ACTION Cube series frequency converters, enabling seamless integration into the Profibus DP network.

Chapter 1: Hardware Installation and Profibus DP Physical Layer Specification

The CM-PDP module, as an extension component of the frequency converter, needs to be installed in slot B of the device. Proper installation and bus networking are prerequisites for stable communication.

1.1 Key points of module assembly

According to the guidelines in Chapter 3 of the manual, the assembly process should pay attention to the following key points:

Safe power-off: Before installing the module, it is necessary to ensure that the frequency converter has completely cut off the power supply and that the DC bus capacitor has been fully discharged (at least wait for 3 minutes).

PE spring grounding: The accompanying PE spring needs to be fixed to the inverter body with M4 screws, and then the communication module should be securely connected to the spring with M2 screws. This step is crucial as it enables a low impedance connection between the Profibus cable shielding layer and the equipment ground (PE), which is the foundation for ensuring EMC performance.

Cover plate treatment: After installation, the pre punched holes on the upper cover plate need to be knocked off to expose the Sub-D 9-pin socket X310.

1.2 Bus Terminal Resistance and Cable Specification

The Profibus DP network requires the activation of termination resistors at the first and last nodes of the physical bus.

Activation method: Implemented through DIP switch S1 on the module (factory default is OFF).

Key warning: Terminal resistance is only effective when the module is powered on. If a terminal node device in the network loses power, its terminal resistance will fail, which may cause the entire bus communication to be interrupted.

Definition of socket: X310 socket follows the standard Profibus DP definition, Pin 3 (RxD/TxD-P, corresponding to line B) and Pin 8 (RxD/TxD-N, corresponding to line A). Special Profibus cables and connectors that meet a transmission rate of 12 MBaud must be used.

Chapter 2: DP Master Station Configuration and PPO Type Selection

The "plug and play" feature of CM-PDP is reflected in its support for Auto-Baud, which does not require manual baud rate setting, but the correct configuration of the main station is the core of communication establishment.

2.1 GSD file import and site address setting

The GSD file (VEC_0696. GSD) is the "ID card" used by the DP master station to identify the attributes of slave station devices.

Import: In the hardware configuration tool (such as Siemens STEP7), install the file through "Extras ->Install new GSD". After installation, the device will be visible in the "PROFIBUS-DP ->Additional Field Devices ->Drives ->ACT 10" directory.

Station address setting: Set the node address through the parameter Profibus Node-ID 391 (range 0-126) of the frequency converter. Note: After the address modification is saved, the frequency converter will automatically perform a reset to apply the new address. In the same Profibus network, the station address of each node must be unique.

2.2 PPO Type Selection and Scanning Cycle

CM-PDP supports four types of PPO (Parameter Process Data Object), corresponding to different data exchange efficiencies (Chapter 7):

PPO1: 4 Words PKW (parameter channel)+2 Words PZD (process data channel), suitable for scenarios that require frequent reading and writing of parameters and moderate real-time requirements, with a scanning cycle of 32ms.

PPO2：4 Words PKW + 6 Words PZD， Provide the richest process data (such as multiple actual values) with a scanning period of 32ms.

PPO3: Only 2 Words PZD, no parameter channel, designed for scenarios that pursue ultimate high-speed data interaction, with a scanning cycle of only 16ms.

PPO4: Only 6 Words PZD, suitable for occasions that only require pure process data communication, with a scanning cycle of 32ms.

In tools such as STEP7, drag and drop the selected PPO objects (such as "PPO2: 4 Words PKW, 6 Words PZD") to the inverter slave station.

Chapter 3: PKW Channel - Inverter Parameter Reading and Writing Mechanism

The PKW (Parameter Identification Value) channel is the essence of the Profidrive protocol, which defines how the master station can read and write access any parameter of the frequency converter through the bus.

3.1 Handshake Rules for Request and Response

PKW's communication follows a strict master-slave "handshake" process (Chapter 10.1.5):

Initial state: The "Task Identifier" (AK) of the master station and the "Response Identifier" (AK) of the slave station are both 0.

Initiate request: The master station writes the task identifier (such as AK=1 for reading parameters, AK=2 for writing integers), and fills in the parameter number (PNU) and index (IND).

Waiting for response: The master station polls and waits for the slave station to change the response identifier from 0 to non-zero (such as AK=1 indicating successful read response, AK=7 indicating execution failure).

End transaction: After the master station reads the data, it writes the task identifier back to 0, and the slave station then resets the response identifier to 0, ending a complete parameter access.

3.2 Key Data Structures

PKE (Parameter Identification): Includes task/response identification (AK) and parameter number (PNU, range 1-999). For example, when accessing parameter 480 (fixed frequency 1), the PNU is 0x1E0.

IND (Index): Used to specify the dataset (DS). For parameters that support dataset switching, IND=1-4 corresponds to datasets 1-4. Key tip: When cyclic writing is required (such as real-time updating of PID setpoint), to avoid burning EEPROM and running out of life, the index value should be incremented by 5 (e.g. IND=6 indicates writing to dataset 1 but only remaining in RAM).

PWE (parameter value): 16 bit parameters occupy PWE1 (low word), 32-bit parameters (such as frequency value) occupy PWE_High+PWE_Low.

3.3 Interpretation of Exception Codes

When the response identifier AK=7 (task cannot be executed), the error code can be read from the low byte of PWE_Low:

1: Invalid parameter number

2: Parameter value exceeds the limit

3: Wrong dataset

9: Inconsistent dataset values (commonly seen when reading IND=0 but different values in four datasets)

101: Parameters cannot be read, etc.

Chapter 4: PZD Channel - Real time Process Data and State Machine Control

The PZD (Process Data) channel is the core of Profibus DP for real-time drive control, which is divided into control word/status word (PZD1) and setpoint/actual value (PZD2-PZD6).

4.1 PZD1: "Three modes" of control word and state machine

The parameter Local/Remote 412 determines the control source of the frequency converter, which mainly involves three modes for Profibus (Chapter 10.2.1):

Mode 0- Contact Control: Controlled by hard wired digital input, PZD1 control word is invalid.

Mode 1- State Machine Control (Recommended): Standard Profidrive Control Mode. Trigger the state machine jump by controlling the combination of word positions.

Startup process: 0x06 (Shutdown) ->0x07 (Switch On) ->0x0F (Enable Operation). This is a universal power on startup sequence.

Shutdown and Emergency Stop: 0x02 triggers Quick Stop, which will use the emergency stop ramp to decelerate. The status word reflects states such as' ready to run ',' operation enabled ', and' fault '.

Mode 2- Remote Contact: Control words Bit 0-5 are directly mapped to virtual digital inputs (S1IND-S6IND), used to simulate hard wired start and stop logic.

Special Reminder (Chapter 10.2.3.2): Transition 5 (from "Operation enabled" to "Ready") can be customized with the parameter State transition 5 392 for shutdown mode:

0: Free Parking (Coast)

1: DC braking (V/f control mode only)

2: Slope deceleration parking (default)

4.2 PZD2-PZD6: Given values and actual values from multiple channels

Calibration of Given Values (Chapter 10.2.5): The given values are sent in standardized form, with -100% corresponding to 0x0000 and+100% corresponding to 0x4000. The reference benchmark is defined by the parameter Profibus Reference 390 (if set to 0, refer to Rated frequency 375). For example, if Profibus Reference=60.00Hz and 0x2000 (50%) is sent, the given frequency is 30.00Hz.

Extended Actual Values (PPO2/PPO4): In PPO2 and PPO4, PZD3-PZD6 maps rich actual values, such as PZD3 for absolute current, PZD4 for active current, PZD5 for warning codes, and PZD6 for fault codes (Chapter 10.2.7).

PPO-OUT data as a global source (Chapter 10.2.8): This is a highly flexible feature. The output data of PZD3-PZD6 in PPO2/PPO4 can serve as a signal source for the internal functions of the frequency converter. For example, PZD3 can serve as a setpoint source for technical controllers, while a certain bit of PZD4 can directly control the digital output.

Chapter 5: SYNC/FREEZE Command and Advanced Diagnosis

5.1 SYNC and FREEZE commands

FREEZE: Synchronize and lock all input data from slave stations, allowing the master station to read device status snapshots at the same time.

SYNC: Synchronize and lock the output data of all slave stations. The master station can configure the output of multiple slave stations, and then use the UNSYNC command to take effect simultaneously, achieving precise synchronization of multi axis motion.

5.2 Troubleshooting and Diagnosis

Status words: Bit 7 (Warning) and Bit 15 (Warning 2) are indicator lights for quickly determining the health status of the device. Warning 2 usually indicates that a trip is about to be triggered.

Communication failure: Fault code F2061 indicates module failure, F2062 indicates DP master station communication interruption (OFF), F2065 indicates configuration error (usually caused by PPO type mismatch).

Actual value monitoring: The two special parameters DP Master OUT 281 and DP Master IN 284 (only available for VPlus software viewing) can intuitively display the raw hexadecimal data of the current bus interaction, making them a powerful tool for locating communication logic problems.