Modbus; Modbus (L1, L2) For Prm; Exported (Read) Modbus Registers - SKF Multilog On-Line System IMx-M User Manual

Protection

Modbus

7. By clicking OK in the lower right, the channel configuration is finished.
Modbus

Modbus (L1, L2) for PRM

The Modbus protocol allows for only one master, but many slaves (See
Modbus slaves respond to requests from the Modbus master.
Currently, IMx-M protection part supports Modbus slave functionality only.
A Modbus slave can export (read) or import (write single) values from Modbus registers,
following requests of the Modbus master.

Modbus frame format is RTU.

The request is limited to maximum 57 registers per request.

Refer to
can be read to the Modbus master. Exported Modbus registers provide all of
analog, digital and combined channel measurement values and status, system
status, Modbus statistics and information on protection module, firmware, IMx-M
Manager and PRM configuration.

Refer to
functions that can be written from the Modbus master. Note that the imported
Modbus registers are limited to command registers.
To configure RS485 Modbus L1 and L2 settings via IMx- M Manager, refer to
in Assigning Protection Settings (PRM) chapter.

Exported (Read) Modbus Registers

An IMx-M protection part Modbus slave provides channel status and has all of its
measured analog and digital channels available for export at the request of the Modbus
master.
Important facts

Only the defined registers can be accessed by an Export/Read function.

It is not possible to read multiple register blocks where there are gaps of undefined
registers in the address range between the blocks. e.g. A multiple block of register
numbers from 513 to 576 cannot be read since there are gaps (undefined
registers) between 529 and 560.

Exported (Read) registers are Read-only.
Notes on Implementation

Modbus registers translate according to the table "Exported (Read) Modbus
registers", below.

The read function code is 0x04.
2 - 180
Yellow hatching on green – Alert hysteresis.
Red Hatching on yellow – Danger hysteresis.
Exported (Read) Modbus Registers
Imported (Write Single) Modbus Registers
RS485
for the detailed available functions that
for the detailed available
SKF Multilog On-Line System IMx-M
Modbus).
Modbus
User Manual