
If a terminal is used to send commands or data, you can hook it up to the scale data cable,
usually by way of a DB9 or DB25 connector, set the line parameters, and start using it right
away. If a computer is to be used, you must use a communications program in order to
communicate with the scale. In either case, you must check the line settings of the scale
and computer or terminal to make sure they match. These are the baud rate, data bits, and
parity settings. The 4200 comes standard with the most common settings, which are:
baud rate = 9600, data bits = 8, parity = n. These can be changed to match the computer
or terminal (see Section 6, parameters 13a and 14a), or the computer or terminal settings
can be changed to match those of the 4200.
The 4200 also has an option setting to enable or disable handshaking (see Section 6,
parameter 19). If handshaking is on, the scale will return an asterisk upon recognition of a
valid command and completion of the specified task. If the command is not recognized,
the scale will return a question mark. This helps to ensure that a command was recognized
and carried out successfully.
PORT 1 (DUPLEX) COMMAND SUMMARY
The Model 4200 has a standard set of commands that enter and return information from
the scale via port 1. The commands must always be preceded by the address of the
indicator, which is 01 by default. No other addresses need be used, except in the case
where multiple indicators are connected in a network, which would require a separate
address for each indicator. All indicators will respond to an address of 00, regardless of
the indicator's address. This is intended to be used as a broadcast address, allowing a
single command to be sent to multiple indicators simultaneously. Send a carriage return
(with or without a line feed) after each command to complete the transmission.
General Scale Commands
General commands are mostly one-character commands that accomplish push-button
functions. Remember to precede each command with the address of the scale, and follow
each command with a carriage return.
G
Selects the gross display mode.
N
Selects the net display mode.
P
Sends one transaction from the scale as specified in Section 6. This will default to
transmit from the simplex serial port unless prefixed with the "Q"
command.
V
Causes a unit conversion as set up in Section 6.
Z
Zeros the scale as the ZERO push-button would on the face of the scale.
Section 8 Serial Communications
53