VM1000 Series
‐116‐
Responding Information of Auxiliary:
ADR 02H
CMD 06H
High bit of data address F0H
Low bit of data address 0AH
High bit of data content 13H
Low bit of data content 88H
CRCCHK LOW BIT
The CPCCHK is still need to be
calculated
Table 6-5 The Auxiliary Written into Responding Information Frame Format
Checking Mode -CRC:
When using RTU frame format, the message contains error detection domain that
based on CRC. CRC field checks the contents of the whole message. CRC field is
two bytes and includes a 16-bit binary value. After calculated by the transmission
equipment, it is added to the message. The receiving device recalculates the CRC
that received message, and compares it with the value that received in the CRC field.
If the two CRC values are not equal, it means that the transmission is not correct.
CRC is first stored in 0xFFFF, then invoke a continuous procedure to process the
message with 8-bit byte and the current value of register. Only each character 8Bit
data is valid for CRC, while start/ stop bits and the parity check bits are invalid. In
CRC, each 8-bit character is different from the register contents or (XOR). The
result moves to the least significant bit and most significant bit is filled with 0. If
LSB is 1, the register is independently different from preset value. If LSB is 0, it will
not implement. The whole procedure is repeated eight times. After completing the
last bit (the 8th bit), the next 8-bit byte is different from the current value of register
again. The final value of the register is the CRC value of all bytes in the message
after the execution. When CRC is added to the message, the low byte will be added
first and followed by the high byte.
To Next Page
Loading...
Need help?
General
