Modbus Register Map; Viewing/Setting Modbus Parameters; Communication Protocol - Eaton Power Xpert PXR Series Manual

11 Modbus register map

11 Modbus register map
A ModbusRTU communication module is integrated to the trip unit for certain styles.

11.1 Viewing/setting Modbus parameters

Modbus connection parameters can be viewed and set from LCD display, via PXPM and
Modbus communication. To view from Modbus communication, the settings are stored
beginning at register number 404000 and extending through 404003 and may be read by
using function code 03 or 04, listed in the following table. These four registers can be
written one by one with function code 06 to change Modbus setting. If the data written into
these registers is out of range, it will result in an exception code 03.
Register
Dec HeX
4000 F9F
4001 FA0
4002 FA1
4003 FA2

11.2 Communication protocol

Only the Modbus RTU communication mode is recognized by the trip unit. The trip unit can
support a maximum of 122 registers (244 data bytes) in a single Modbus transaction. The
trip unit responds to Modbus function codes 02, 03, 04, 06, 08 and 16. Auxiliary power (24 V
DC) is required for communications functionality.
To accommodate Modbus master that can only access to register 9999, some Eaton regis-
ters initially assigned above 9999 have been assigned dual access, both at the origi¬nal
register (to provide compatibility) and at a new register assignment below 9999. The
format is given as low/high register numbers followed by (low16/high16 Modbus register
addresses). An example is: 4xxxx/4yyyyy (XXXX+116/YYYY+116).
11.2.1 Communications protocol options
Configuring any or all registers 402001/425345 through 402003/425347(0x07D0/0x6300
through 0x07D2/0x6300) is accomplished using a write function code "06" or "16" .
11.2.1.1 Gap in block data
Non-volatHle regHster 402001/425345(0x07D0/0x6300) = 0t: Block read HncludHng HnvalHd
data
If zero when client request a block of data that includes unused registers, the trip unit
will respond without errors, however the unused register may contain invalid data such as
(0xFFFFFFFF16) for invalid unsigned fixed-point, (0x8000000016) may be used to represent
an invalid signed fixed-point object and (0x7FF2000016) may be used to represent an invalid
floating-point object.
Non-volatHle regHster 402001/425345(0x07D0/0x6300) <> 0t: block read error wHth HnvalHd
data (Factory Default)
If none-zero (factory default value), when the client requests a block read of data that
includes unused register the illegal data object exception code 02 will be issued from the
trip unit. No data from that block will be read.
N otet: If the starting register number accesses an invalid object, the illegal data object
exception code 02 will be issued, regardless of this configuration setting.
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modbus parameters
Descriptions
Slave ID
Baud rate
Parity
Stop bit
Data range
001 – 246 (factory default = 2)
00 = 9600 bit/s
01 = 19200 bit/s (factory default)
02 = 38400 bit/s
03 = 57600 bit/s
00 = None
01 = Odd
02 = Even (factory default)
00 = 1 bit (factory default)
01 = 2 bits