KEB F5 COMBICOM ModBus

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Summary

ModBus Interface

Ordering Information

Details available part numbers for the ModBus operator and related accessories.

Hardware Description

Describes the physical components and connectors of the ModBus interface.

ModBus Transmission Speed

Explains how to configure and adjust the ModBus communication speed.

Diagnosis Interface

Information on connecting a PC for diagnosis and parameterization.

Functions

Slave Addressing

Configuration of the ModBus slave address for device communication.

Parameter Addressing

Methods for accessing inverter parameters via ModBus register addresses.

ModBus Functions

Overview of standard and KEB-defined ModBus function codes.

User Defined Functions Defined By KEB

Details on KEB's custom ModBus functions (e.g., Read/Write Registers32).

Fieldbus Watchdog

Configuration and behavior of the fieldbus supervision watchdog timer.

Annex

Table of Operator Parameters

A consolidated table listing operator parameters, their addresses, and data lengths.

Error Codes of Exception Response

Lists and explains error codes returned by the ModBus interface.

The KEB COMBICOM is a ModBus operator and diagnosis interface, designed to facilitate communication and control of KEB COMBIVERT frequency inverters. This device acts as a slave interface within a ModBus network, allowing for parameter access, monitoring, and configuration of the connected inverter.

Function Description

The primary function of the KEB COMBICOM is to provide a ModBus interface for KEB frequency inverters. It supports both RS232 and RS485 transmission standards, offering flexibility in network integration. The device allows for reading and writing of inverter parameters, enabling comprehensive control and monitoring from a ModBus master.

Parameter addressing is organized into different groups:

0000(hex) - 1FFF(hex): This range is for parameters accessed through mapping lists. The starting address of these mapping parameters can be adjusted via MDB_MapStartAddr_Rd/Wr.
2000(hex) - 5EFF(hex): This area maps inverter control board parameters using a fixed algorithm, where FI-Parameter Address = ModBus Register Address – 2000(hex). Access in this area is done with indirect set addressing (using FR.09), requiring the set indicator (FR.09) to be configured prior to access for parameters in different sets.
5F00(hex) - 5FFF(hex): This block is dedicated to operator parameters.

The KEB COMBICOM supports standard ModBus functions such as:

3: Read Holding Registers
4: Read Input Registers
6: Preset Single Register
16: Preset Multiple Registers

These predefined functions are designed for 16-bit data access and operate with indirect set addressing (FR.09) for inverter parameters. To address parameters with 32-bit data length, KEB has defined two additional user-defined ModBus functions:

Function 100: Read Registers32: For reading several 32-bit registers (indirect set addressing through FR.09).
Function 101: Write Registers32: For writing several 32-bit registers (indirect set addressing through FR.09).

These 32-bit functions are particularly useful for accessing specific KEB frequency inverter parameters that require higher data precision. The device also incorporates mapping lists for both reading and writing, allowing access to both 16-bit and 32-bit parameters via functions 3, 4, and 16. The length of these mapping lists is programmable via MDB_MapNr_Rd/Wr, with a maximum of 100 words (16-bit).

Important Technical Specifications

ModBus Transmission Speed: Configurable via inverter parameter SY.07, with supported bitrates including 1200, 2400, 4800, 9600, 19200, 38400, and 55500 Bit/s. The operator reads this value during initialization.
Slave Addressing: The ModBus address is determined by the operator parameter MDB_SlaveAddr_OP. If MDB_SlaveAddr_OP is 255 (decimal), the address is taken from the inverter address (SY.06). If SY.06 is 0 (reserved for broadcast), ModBus activities are disabled. Otherwise, MDB_SlaveAddr_OP directly sets the ModBus address (1-247).
Data Lengths: Parameters can have 1-byte, 2-byte, or 4-byte data lengths. The 32-bit parameters (4-byte) require two entries in the mapping list for full access.
Serial Interface: Supports RS232 and RS485 standards via a SUBD9 (Female) connector.
LED Indicators:
- MDB (Green): Shines when a ModBus service is running.
- ERROR (Red): Blinks for frequency inverter error, shines constantly when ready for operation, and is off if there's no power supply.
Diagnosis Interface (X6B): Used for connecting to a PC via an HSP5 cable and adapter for diagnosis and parameterization using KEB Combivis software.
ModBus Connector (X6C): SUBD9 female connector for ModBus communication.

Usage Features

Flexible Parameter Access: The KEB COMBICOM allows for both direct and indirect parameter access, catering to various application needs. Indirect access is particularly useful for managing parameters across different sets of the inverter.
User-Defined Functions: The inclusion of Function 100 (Read Registers32) and Function 101 (Write Registers32) provides robust support for 32-bit parameters, which are common in KEB frequency inverters.
Watchdog Functionality: The device supports a fieldbus watchdog, configured by Watchdog_Inhibit and Watchdog_Activation parameters. This feature enhances system reliability by monitoring communication and triggering predefined actions (via Pn.05 and Pn.06) in case of communication timeouts. Watchdog_Inhibit defines events that reset the watchdog, while Watchdog_Activation defines events that activate it.
Operator Parameters: A dedicated block of operator parameters (5F00h to 5FFFh) allows for fine-tuning of the ModBus interface behavior, including protocol configuration (MDB_ProtCfg), slave address source (MDB_SlavAddr_OP), mapping list start addresses (MDB_MapStartAddr_Rd/Wr), and mapping list lengths (MDB_MapNr_Rd/Wr).
Command Execution: The MDB_Command parameter (5F31h) allows requesting specific commands in the ModBus operator, such as setting operator parameters to default values.
Diagnosis Capabilities: The diagnosis interface (X6B) and associated parameters like Diag Error Counter (0183h), DiagRsp.DelayTime (0184h), and Diag Baudrate (0185h) enable detailed troubleshooting and monitoring of the communication link.

Maintenance Features

Error Code Reporting: The device provides specific error codes for exception responses, such as illegal function, illegal data address, slave device failure, and timeout at transfer to frequency inverter control. This aids in diagnosing communication issues.
Software Date (0182h): Provides information about the operator's software version, useful for compatibility checks and updates.
HSP5_Max_InvBusy_Retries (0186h): Configures how often the ModBus operator retries a request if the inverter responds with an "inverter busy" error, helping to manage communication under heavy load or temporary inverter unavailability.
HSP5 Tout Cnt (0187h): Counts the occurrences of timeouts on the interface between the ModBus operator and the frequency inverter control, providing a metric for communication stability.
Non-Volatile Saving: Most parameter changes are immediately active and non-volatilely saved, ensuring that configurations persist across power cycles.

The KEB COMBICOM is a robust and versatile interface, crucial for integrating KEB frequency inverters into ModBus-based control systems, offering extensive control, monitoring, and diagnostic capabilities.