ABB ACS355 series, User Manual

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324 Fieldbus control with embedded fieldbus
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Actual value scaling
The scaling of the integers sent to the master as Actual values depends on the
selected function. See chapter
Actual signals and parameters on page 179 .
Modbus mapping
The following Modbus function codes are supported by the drive.
Function Code
hex (dec) Additional information
Read Multiple
Holding
Registers 03 (03) Reads the contents of registers in a slave device.
Parameter sets, control, status and reference values are mapped
as holding registers.
Write Single
Holding
Register 06 (06) Writes to a single register in a slave device.
Parameter sets, control, status and reference values are mapped
as holding registers.
Diagnostics 08 (08) Provides a series of tests for checking the communication between
the master and the slave devices, or for checking various internal
error conditions within the slave.
The following subcodes are supported:
00 Return Query Data: The data passed in the request data field is
to be returned in the response. The entire response message
should be identical to the request.
01 Restart Communications Option: The slave device serial line
port must be initialized and restarted, and all of its communication
event counters cleared. If the port is currently in Listen Only Mode,
no response is returned. If the port is not currently in Listen Only
Mode, a normal response is returned before the restart.
04 Force Listen Only Mode: Forces the addressed slave device to
Listen Only Mode. This isolates it from the other devices on the
network, allowing them to continue communicating without
interruption from the addressed remote device. No response is
returned. The only function that will be processed after this mode
is entered is the Restart Communications Option function
(subcode 01).
Write Multiple
Holding
Registers 10 (16) Writes to the registers (1 to approximately 120 registers) in a slave
device.
Parameter sets, control, status and reference values are mapped
as holding registers.
Read/Write
Multiple
Holding
Registers 17 (23) Performs a combination of one read operation and one write
operation (function codes 03 and 10) in a single Modbus
transaction. The write operation is performed before the read
operation.