12.2.2
Read window (output area)
Data are transferred from the slave (PR 5410) to the master in this window.
Byte 0
Read data: MSB
Byte 1
Read data: MSB
Byte 2
Read data: MSB
Byte 3
Read data: LSB
Byte 4
Read_Value_Select
Byte 5
General system bits:
-
write_active
-
power_fail
-
analog error
Byte 6
Status bits
Byte 7
Status bits
The first four bytes are used to read a data value.
The register number of the data is mirrored in byte 4 by the write window, when data is
available.
Bytes 5, 6, and 7 contain status bits independent of the read data.
12.2.3
Reading and writing data
The number of data vastly exceeds the size of the read/write window. For this reason,
data is addressed with
Write_Value_Select
and
Read_Value_Select
. To do this, the first
six bytes of the write window and the first five bytes of the read window are required.
These can be used by the master to write data in the PR 5410: e.g., a limit value is set to
100 kg. The master can also read weight values or other data from the PR 5410. The write
and read windows are always required for this. Safe data exchange is ensured by a write
and a read procedure.
For reading status bits and for writing direct control bits, however, no procedure is
required. The general system bits and the status bits are always provided and need not be
requested. The direct control bits are also available continuously.
12.2.3.1
Reading data
Procedure:
12.2.3.2
Writing data
Procedure:
1.
Write the register number as
Read_Value_Select
in byte 4 of the write window
(e.g., net weight).
2.
Wait until
Read_Value _Selected
in byte 4 of the read window is equal to
Read_Value_Select
in byte 4 of the write window.
Now the value is available in bytes 0 to 3.
1.
Wait until
Write_Active
= 0 in the read window (ready to receive new data).
2.
Write the value in bytes 0 to 3.
3.
Write the register number in byte 5 (
Write_Value_Select
).
X3 Process Indicator PR 5410
12 Fieldbus interface
Minebea Intec
EN-294
