Modbus Gateways - User Guide
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Version EN-092019-1.21
The following diagram shows the operation modes and corresponding values.
Operation mode
Value
Meaning
Offline
1
Cyclic data exchange is deactivated.
Stop
2
Cyclic data exchange is activated, but only input data is read (Fail Safe
Mode).
Run
3
Cyclic data exchange is activated. Input data is read and output data
is written.
Note
The PROFIBUS master cannot be set to Offline mode by writing into the status register.
5.1.2
Device information
The Modbus Gateway provides the status and the Ident number of the connected PROFIBUS devices.
The device status is provided per segment in a Modbus register for every device station address between 1
and 126. Station address 0 is assigned to the master. The register number of a specific station address is
the sum of the base register number of the respective segment and the station address. The
for the segments are 8500 (segment 0), 8628 (segment 1), 8756 (segment 2) and 8884
(segment 3). The register number for a device on station address 2 in the first segment is therefore 8502.
The register number can also be found in the configuration report (see
Status Register
in image below).
For details on how to generate a configuration report, see the video
.
The high byte of the status register is the so called Life Sign. The value increases by 1 every time input data
is read successfully from the device.
The Ident number of the devices is provided per segment in a Modbus register for every device station
address between 1 and 126. Station address 0 is assigned to the master. The register number of a specific
station address is the sum of the base register number of a segment and the station address. The base
register numbers for the segments are 9012, 9140, 9268 and 9396. The register number for a device on
station address 2 in the first segment is therefore 9014.
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