Modbus Protocol Technical Data - Drive Only - ABB ACH580 Series User Manual

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Modbus protocol technical data – Drive only
System overview
The Modbus® protocol was introduced by Modicon, Inc. for use in control
environments featuring Modicon programmable controllers. Due to its ease of use
and implementation, this common PLC language was quickly adopted as a de-facto
standard for integration of a wide variety of master controllers and slave devices.
Modbus is a serial, asynchronous protocol. Transactions are half-duplex, featuring a
single Master controlling one or more Slaves. While RS232 can be used for point-to-
point communication between a single Master and a single Slave, a more common
implementation features a multi-drop EIA 485 network with a single Master
controlling multiple Slaves. The ABB E-Clipse bypass features EIA 485 for its
Modbus physical interface.
RTU
The Modbus specification defines two distinct transmission modes: ASCII and RTU.
The ABB E-Clipse Bypass supports RTU only.
Feature summary
The following Modbus function codes are supported by the system.
Read Coil Status
Read Discrete Input
Status
Read Multiple
Holding Registers
Read Multiple Input
Registers
Force Single Coil
Write Single
Holding Register
Diagnostics
Force Multiple Coils 0x0F
Write Multiple
Holding Registers
Read/Write Multiple
Holding Registers
Embedded fieldbus
Function Code (Hex)
0x01
0x02
0x03
0x04
0x05
0x06
0x08
0x10
0x17
ACH580 E-Clipse bypass and packaged drive user manual
Read discrete output status. For the system, the individual bits of
the control word are mapped to Coils 1...16. Relay outputs are
mapped sequentially beginning with Coil 33 (e.g. RO1=Coil 33).
Read discrete inputs status. For the system, the individual bits of
the status word are mapped to Inputs 1...16 or 1...32, depending
on the active profile. Terminal inputs are mapped sequentially
beginning with Input 33 (e.g. DI1=Input 33).
Read multiple holding registers. For the system, the entire
parameter set is mapped as holding registers, as well as
command, status and reference values.
Read multiple input registers. For the system, the 2 analog input
channels are mapped as input registers 1 and 2.
Write a single discrete output. For the system, the individual bits
of the control word are mapped to Coils 1...16. Relay outputs are
mapped sequentially beginning with Coil 33 (e.g. RO1=Coil 33).
Write single holding register. For the system, the entire
parameter set is mapped as holding registers, as well as
command, status and reference values.
Perform Modbus diagnostics. Subcodes for Query (0x00),
Restart (0x01) and Listen Only (0x04) are supported.
Write multiple discrete outputs. For the system, the individual bits
of the control word are mapped to Coils 1...16. Relay outputs are
mapped sequentially beginning with Coil 33 (e.g. RO1=Coil 33).
Write multiple holding registers. For the system, the entire
parameter set is mapped as holding registers, as well as
command, status and reference values.
This function combines functions 0x03 and 0x10 into a single
command.
Description