Serial Communication
Output Formats
VT300 Technical Manual, Rev. A4
53
Doc
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TM-VT300-EN
Master-Slave Commands
List of Commands
Command Hex Description
Time Slave
response
?
3F
UPLOAD WEIGHT & STATUS
50 ms
WEIGHT
@
40
RESET
SLAVE
15ms
NONE
K
4B
DOWNLOAD
KEY
0.1
ms
NONE
“?” Command: Upload Status
It is the main command used to poll the slave or slaves, which reply with the current
weight being measured or with a message if bit0 of status byte is ‘1’. In the normal
state the slave will respond within 3-4 character time.
(e.g. with 9600 baud, the character time
≈
1msec, the master should expect
reception of STX from the slave within 5msec after the ETX was transmitted from the
master).
Master Transmission
STX ADD
?
0
BCS2
BCS1 ETX
Example:
STX ADD ? 0 BCS2 BCS1 ETX
Hex
2 41
3F
30
3C 34
3
Ascii
STX A ?
0 < 4
ETX
ADD is one of the address sets in
SYSTEM > SET > 2COM > OPERATION: M/S A-Z
CheckSum is calculated as the XOR sum of all data characters, ETX excluded.
E.g. 02 XOR 41 XOR 3F XOR 30 = 4C (BCS1 = 30+C=3C, BCS2 = 30+4=34)
Slave Response
STX ADD ? 0 STATUS
BYTE WEIGHT X Y Z BCS2 BCS1 ETX
WEIGHT = 5 decimal point if any.(ASCII,MSD FIRST)
X = Scale number
0 = Scale 1 + Scale 2
1 = Scale 1
2 = Scale 2
