ProfiBus Interface PR 5211 Instrument Manual
EN-56 Sartorius
6.1.1 Write Window (Input Area)
In this window, data are transmitted from master to slave
(PR 5211).
The first four bytes are used only for writing a data value.
The register number is written in byte 5.
Bytes 6 and 7 contain bits in direct access independent of
the write data.
After a 0-1 transition of the relevant bit, the command is
executed.
Byte 0 Write data: MSB
Byte 1 "
Byte 2 "
Byte 3 Write data: LSB
Byte 4 Read_Value _Select
Byte 5
Write_Value _Select
Byte 6 Direct control bits
Byte 7 Direct control bits
6.1.2 Read Window (Output Area)
In this window, data are transmitted from slave (PR 5211) to
master.
The first four bytes are used for reading a data value.
The register number is mirrored by the write window in
byte 4, when the data are available.
Bytes 5, 6 and 7 contain status bits independent of the read
data.
Byte 0 Read data: MSB
Byte 1 "
Byte 2 "
Byte 3 Read data: LSB
Byte 4 Read_Value _Selected
Byte 5 General system bits:
- Write_Active
- Power_fail
- ADU_Error …
Byte 6 Status bits
Byte 7 Status bits
6.1.3 Data Reading and Writing
The number of data exceeds the size of the write/read windows by far. Therefore, the datas are addressed
with Write_Value_Select and Read_Value_Select. For this purpose, the first six bytes of the write window
and the first five bytes of the read window are required. Thus the master can describe data in PR 5211: e.g.
a limit value shall be set to 100 kg. Weight values or other data can also be read out of the PR 5211 by the
master. For this, the write and the read window are always required. Thereby, safe data exchange is ensured
by a write and a read procedure.
For reading status bits and writing direct control bits, however, no procedure is required. The general system
bits and the status bits are always present and need not be requested. The direct control bits are also
continuously available.
Procedure for Data Reading:
1. Write the register number into byte 4 of the write window (e.g. net weight) as a Read_Value_Select.
2. Wait, until in the byte 4 of the read window, the Read_Value _Selected is equal to the
Read_Value_Select
in the byte 4 of the write window.
3. Now, the value is available in byte 0 to 3.
Procedure for Writing Data:
1. Wait, until
Write_Active
= 0 in the read window (ready to receive new data).
2. Write value in byte 0 to 3.
3. Write register number in byte 5 (Write_Value_Select)
4. Wait, until Write_Active
= 1 (acknowledges data reception)
5. Write 0 into byte 5 (Write_Value_Select) -> Write_Active will go to 0.
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