Minebea Intec PR5900 - 8 Fieldbus Interface

8 Fieldbus interface
8.1 General notes
The PR 5900 can be turned into a eldbus slave by inserting a eldbus interface card in
Option‑FB. This enables one or more devices to be included under a communication
master (e.g., Siemens S7 probus).
Up to 4 weighing points may be addressed over the eldbus interface.
The update time is 50 ms.
Conguration of the interface is carried out in the device under [System setup] - [Fieldbus
parameters]; see Chapter 4.6.
The eldbus exchanges its data cyclically with each slave. That means: In each cycle, the
entire data range is written and read, even if there are no changes to the data content.
Concept denition
Term/Abbreviation Description
Master Fieldbus master, usually an SPS
Slave Fieldbus device
MOSI Master Out Slave In = data is written from the SPS via the
eldbus to the device.
MISO Master In Slave Out = data is returned from the device via the
eldbus to the SPS.
8.2 Scale protocol
If scales A and B are congured, the interface works with a 16 (2 x 8) byte write window
and a 16 (2 x 8) byte read window. The windows are assigned to the weighing points.
8.2.1 Data exchange range
Overview
Byte 0, 1, 2, 3 4 5 6, 7
MOSI Write data Read_Value_Select Write_Value_Select Control bits
(control bits)
MISO Read data Read_Value_Selected Status bits
(status bits)
Status bits
(status bits)
Write window (MOSI)
Byte Field Description
0 Write data (MSB)
1 Write data
2 Write data
3 Write data (LSB)
Contains the data to be written,
e.g., analog output.
Process Controller Maxxis 5 PR 5900 8 Fieldbus interface
Minebea Intec EN-346