Chapter 9 Appendix-Serial interface network use and communications protocol
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transferred data is
+10m3! F7 (CR), "!" means the character before it is the sum
character, and the verified sum of the two bytes after it is
(2BH+31H+32H+33H+34H+35H+
36H+37H+45H+2BH+30H+6DH+33H+20H
=(2)F7H)
Note: there can be no data before "!", and also may be a blank character.
Prefix W
Usage of prefix W: W+ numeric string address code +basic command.
Value range of the numeric string is 0~65535, except 13 (0DH carriage
return), 10 (0AH line feed), 42 (2AH *) and 38 (26H &). If the
instantaneous velocity of No. 12345 flowmeter is to be accessed, the
command W12345DV(CR) can be issued. Corresponding binary code is
57H, 31H, 32H, 33H, 34H, 35H, 44H, 56H and 0DH
Function sign &
Function sign & can add up to 5 basic commands (Prefix P is allowed)
together to form a compound command sent to the flowmeter together.
The flowmeter will answer simultaneously. For example, if No. 4321
flowmeter is requested to simultaneously return: 1] instantaneous flow, 2]
instantaneous flow velocity, 3] positive total flow, 4] energy total, 5] AI1
analogous input current value, the following command is issued:
W04321PDQD&PDV&PDI+&PDI-&PDIN(CR)
Simultaneously returned data are likely as follows:
+0.00m3/d! AC(CR)
+0.00m/s! 88(CR)
+10m3! F7(CR)
+0.0m3! DA(CR)
+0.0 m3! DA(CR)
9.3.2. MODBUS communication protocol
This MODBUS Protocol uses RTU transmission mode. The Verification Code uses
CRC-16-IBM (polynomial is X16+X15+X2+1, shield character is 0xA001) which is
