Rishabh RISH CON - Hz, Руководство по эксплуатации, Страница: 39 / 60

Function code
03
04
16
Read Holding Registers
Read input Registers
Presets Multiple Registers
Read content of read /write location ( 4X )
Read content of read only location ( 3X )
Set the content of read / write locations ( 4X )
Communication Baud Rate is user selectable from the
front panel between 2400, 4800, 9600, 19200 bps.
After sending any query through software ( of the Master), it
must allow 200 ms of time to elapse before assuming that
the frequency transducer is not going to respond. If slave
does not respond within 200 ms, Master can ignore the
previous query and can issue fresh query to the slave.
The each byte in RTU mode has following format:
8-bit binary, hexadecimal 0-9, A-F
2 hexadecimal characters contained in each
8-bit field of the message
4 bytes (32 bits) per parameter.
Floating point format ( to IEEE 754)
Most significant byte first (Alternative least
significant byte first)
Format of
Data Bytes
2 byte Cyclical Redundancy Check (CRC)
Error Checking
Bytes
1 start bit,
8 data bits, least significant bit sent first
1 bit for even/odd parity
1 stop bit if parity is used; 1 or 2 bits if no parity
Byte format
Exception Cases : An exception code will be generated
when frequency transducer receives ModBus query with
valid parity & error check but which contains some other
error ( e.g. Attempt to
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