Pag. 51 of 52
- Protocollo di comunicazione
13.3
Prefixes using
13.3.1 -
P prefix
The prefix P can be added before any command in the above table to have the returning data followed with two
bytes of CRC check sum, which is the adding sum of the original character string.
Take the DI+(CR) command as an example. Assume that DI+(CR) would 10m3(CR)(LF)( the
string in hexadecimal is 2BH, 31H, 32H, 33H, 34H, 35H, 36H, 37H, 45H, 2BH, 30H, 6DH, 33H, 20H, 0DH, 0AH) ,
then PDI(CR) would 10m3!F7(CR)(LF). ‘!’ acts as the starter of check sum which is yielded by
adding up the string 2BH, 31H, 32H, 33H, 34H, 35H, 36H, 37H, 45H, 2BH, 30H, 6DH, 33H, 20H.
Please note that there will be SPACES (20H) before ‘!’.
13.3.2 -
W prefix
The prefix W should be used in the network environment. The usage format is W + digit string which stands for the
IDN + basic command.
The digit string should have a value between 0 and 65534 except 13(0DH), 10 (0AH), 42(2AH,*), 38(26H, &).
For example, if the IDN=12345 instrument is addressed and returning the velocity of that instrument is requested,
the command will be W12345DV(CR).
13.3.3 -
N prefix
The prefix N is a single byte IDN network prefix, not recommended in a new design. It is reserved only for the
purpose of the compatibility with the former versions
Command Connector &
The & command connector can connect up to 6 basic commands to form a longer command so that it will make the
programming much easier.
For example, assume that the measurement of an instrument with IDN=4321 are going to be returned, and (then) all
the following 3 values— (1) flow rate (2) velocity (3)POS totalizer—will be returned simultaneously. The combined
command would be W4321DQD&DV&DI+(CR), and the result would be:
+1.12m3/d(CR)
+3.100m/s(CR)
+10m3(CR)
13.4 Codes for keypad
The codes for the keypad should be used when the instrument is connected with other terminals that operate the
instrument by transmitting the ‘M’ command along with the keypad code. By this function, remote operation of this
instrument can be realized, even via Internet.
Key
Hexadeci-
mal
1Decimal
k2ey code3 ASCII code
Key
Hexadeci-
mal
Decimal
key code
ASCII code
0
30H
48
0
8
38H
56
8
1
31H
49
1
9
39H
57
9
2
32H
50
2
.
3AH
58
:
3
33H
51
3
3BH,0BH
59
;
4
34H
52
4
MENU
3CH,0CH
60
<
5
35H
53
5
3DH,0DH
62
=
6
36H
54
6
3EH
62
>
7
37H
550
7
3FH
63
?
Tab. 14
