Operating Modes (Mode 1, Mode 2); Communication With The Processor - Balluff BIS C-60 3 Serie Handbuch

C60_3-025_825645_1310_e.p65
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Mode Selection
Mode 1
Mode 2
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Basic Procedure
Basic Procedure
for Mode 1
Mode 1: Please see
also 36...49 and
the examples on
50...64.
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Function Description

Operating Modes (Mode 1, Mode 2)

The BIS mode is selected using parameter 5 BIS_Mode .
The following modes are available:
In Mode 1 a read/write job and dataexchange take place according to the standardized Balluff
protocol for bus sysstems. A read/write job must be started with a command identifier, start
address, and the number of bytes to read or write. The controller must also coordinate data
exchange with the processor, i.e. monitor the validity of read data and display the validity of
write data on the I/O buffer area of the respective r/w head.
BIS Mode 1 is recommended,
– when large amounts of data need to be read or written on the data carrier
or
– when different areas on the data carrier are always read or written to.
Mode 2 is a simplified protocol for implementing read/write jobs. The processor indicates
starting of a job simply by setting a bit in the bit header. For write jobs the write data are
immediately sent. The job is automatically carried out by the processor using the previously
parametered values for start address and number of bytes. The controller must only check the
acknowledgement after processing the job and accept the read data in the case of read jobs.
BIS Mode 2 is recommended,
– when smaller amounts of data need to be read or written on the data carrier,
and
– when the same area on the data carrier is always read or written to.
Function Description

Communication with the processor

Communication between the host system and the processor takes place using a fixed proto-
col sequence. Data integrity from the control to the processor and vice-versa is indicated by a
control bit. This bit is used to implement a handshake between the control and the processor.
Following is a simplified sequence for job sent by the controller to the processor for Mode 1
and Mode 2:
1. The control sends a command designator to the processor together with the associated
command parameters and sets a bit (AV bit). This bit indicates to the processor that the
transmitted data are valid and that the job is now beginning.
2. The processor takes the job and sets a bit (AA bit), which indicates this to the control.
3. If an additional exchange of data between the control and the processor is required to
carry out the job, each uses a bit (TI bit and TO bit) to indicate that the control / processor
is now ready for additional data exchange or has accepted the received data.
4. Once the processor has carried out the job correctly, it sets a bit (AE bit).
5. Once the control has accepted all the important data, it indicates this to the processor by
resetting the bit that was set at the beginning (AV bit).
6. The processor now in turn sets all the control bits that were set during the sequence
(AA bit, AE bit) and is ready for the next job.
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english