Transcell Technology PC 150, Руководство по обслуживанию

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Page B-1
APPENDIX B: SERIAL DATA FORMATS INFORMATION
B.1 SERIAL DATA FORMATS
B.1.1 SERIAL DATA FORMATS OVERVIEW
The COM1 serial port is a full duplex RS-232 port designed for connection to a serial
printer, computer, or remote display. Consult the PC Series Operation Manual for
information on pinouts and cable diagrams.
Through the User Menu, you may choose one of the available SDF’s (Serial Data Formats).
These serial data formats emulate certain makes of scales and make up the Application
Layer. From a Data Link Layer perspective, there are two types: Demand and Continuous.
Some SDF’s can be used with both types but most can be used with only one type.
For Demand types, the scale acts as the client and requires a host (usually a PC). The host
issues a command (typically a single ASCII character) and the scale responds with a weigh
data record, a status record or no record depending on the specific SDF chosen.
NOTE: Use Demand types for interfacing to a serial printer. In this case, data output can be
initiated by pressing the PRINT key on the front panel of the scale. (Host is not required).
For Continuous types, host control is not required – but not restricted either. In this type, the
scale automatically transmits a weigh data / status record out of the serial port at the end of
each display update. Continuous types are used to interface to computers, scoreboards,
and other remote devices requiring constant data updating. Host commands, although not
required, are accepted and acted upon.
B.1.2 CONSOLIDATED CONTROLS DEMAND FORMAT
Figure B-1 shows the weigh data record sent to the host when the scale receives a Print
(“P”) command. The same weigh data record is sent out of the serial port if the PRINT key
is pressed on the scale’s front panel. If the weigh data is invalid, the scale does not
respond. See section below for more information.
<STX> <POL> xxxxx.xx <LB/KG> <GR/NT> <CR> <LF>
Polarity:
<SP> = Positive
"–" = Negative
Weight Data
Units:
lb = pound
kg = kilogram Gross/Net:
GR = Gross
NT = Net
Start
Transmission Carriage
Return
Line
Feed
<SP> <SP>
Space Space
FIGURE B-1. Consolidated Controls “Demand” Weigh Data Record
B.1.2.1 RECOGNIZED HOST COMMANDS
These commands are issued from the host to the scale and are single ASCII
characters.
“P” - This command is sent to the scale to print the indicated display. The scale will
not respond if the scale is in motion, positive overload or negative overload.