Brecknell SBI-240, Service Manual

Page: 60 / 78

58 SB
I-240
Service Manual
6 Serial Communication
6.1 Communication Details
1. COM1 is RS232, communication wires come from RS232 connector, and
TXD0, RXD0 and GND are used. Please refer to section 9 for connector
details
2. COM2 is USB used as a virtual RS232, communication wires come from USB
connector, and TXD1, RXD1 and GND are used, Please refer to section 9 for
connector details.
3. The baud rate and byte format is set by USER-COM1/2-BAUD.RT and USER-
COM1/2-BYT.FMT. Responses to serial commands will be immediate, or
within one weight measure cycle of the scale. One second should be adequate
for use as a time-out value by remote (controlling) device.
6.2 Transaction String
The length of each item in a transition string:
l
Reading data --- 6 bytes
l
Data polarity ----1 byte: "-" for negative, and followed the first digit; " " for
positive.
l
Decimal point ---1 byte: "."
l
Measure unit ----1-5 bytes:" lb"," kg","lb:oz","pcs","%". Units are always
lower case, left aligned
l
Current status-- 4 bytes
m
If the weight is over capacity, the scale will return eight "^" characters
(the field of polarity, decimal point, weight data is filled by "^").
m
If the weight is under capacity, it will return eight "_" characters (the field
of polarity, decimal point, and weight data is filled by "_").
m
If the zero point is error, it will return eight "-" characters (the field of
polarity, decimal point, and weight data is filled by "-").
Useless leading 0 before digits is suppressed. Reading weight is right aligned.
Table 6.1 Symbols Used
<LF> Line Feed character (hex 0AH)
<CR> Carriage Return character (hex 0DH)
<ETX> End of Text character (hex 03H)
<SP> Space (hex 20H)
H
1
H
2
H
3
H
4
Four current status bytes
<P> Polarity character: "-" or " "