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IC-KP2-2HB17-2V1D
Commands
Group 2 and 3: FIFO Input Register and FIFO Monitor Input Register
Breakdown of the Areas in the Input Register
Address
(0-based,
decimal)
0 + K
1 + K
2 + K
3 + K
I + K
Table 7.5
FIFO memory
The input data of each channel is stored in two FIFO memories with identical structures. Each
FIFO memory is composed of 32 elements.
The utilization of a FIFO memory is indicated in the first register of the relevant channel. When
registers are read from the memory, the channel content in the memory is shifted along one
memory element. A master can therefore read data from the memory only once.
A protocolling master addresses the device using device ID 2. The protocolling master only has
read permissions for the third group.
Utilization of the FIFO Memory
Utilization indicates the percentage of the FIFO memory occupied by data that has not been
retrieved. If the response data of the device is retrieved at a lower rate than new data is
generated, the FIFO memory overflows and data is lost. In order to avoid data loss, ensure that
utilization remains below 15% by setting a high polling rate.
Utilization Meaning
0
1–100
101
7.7.3
MODBUS commands
The IDENTControl Compact supports the MODBUS commands read holding registers,
write multiple registers and read/write multiple registers.
The MODBUS master issues a command by sending a request. The slave (IDENTControl
Compact) sends a response that corresponds to the MODBUS specifications. If an error
occurs, the response contains an exception code.
Command: write multiple registers (10h)
This MODBUS command (request) starts system commands and read/write commands. You
must know the following parameters to make the request:
34
Byte number of the
identification telegram
-
-
Byte 0
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte N-1
Byte N
K = 0, 1000, 2000, 3000, 4000
I = 4, 5, 6 etc.
No data available
Data available
Data available, but data lost due to FIFO memory overflowing
Use
Reserved
Utilization A
Telegram length, high byte [(N+1) div 256]
Telegram length, low byte [(N+1) mod 256]
Command code (Echo)
Reserved/channel/toggle bit
Status
Reply counter
Data
Data
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