40
Status After Power is Applied
All Setra scales have an internal nonvolatile memory for storing certain status informa-
tion. This memory is not erased when the scale is powered down. All setup functions
(such as print format, minimum pieces, minimum accuracy, baud rate, and tone enable/
disable) and user conversion factors are stored in this memory. As a result, the baud rate
and print format will not need to be reset each time the scale is powered on. However,
if the continuous print mode is desired, follow the procedure previously outlined.
During the first 30 seconds of operation, the scale will run through a self diagnostic
procedure. When it is ready, a wake-up message will be transmitted. (This message can
also be invoked by sending a "w" to the scale or by pressing
0
then
setup/cal
.)
The RS-232 Interface Hardware
Although Setra scales can communicate with almost any RS-232 device, the built-in
interface does not include the complete protocol. Four lines of the standard interface
are used. This should not present any interfacing problems in most applications.
The data format is:
8 data bits
1 start bit
1 stop bit
no parity
framing errors ignored
Use a standard RS-232 cable to connect the external device to the scale, or
construct one following the instructions below.
The female connector pinout, as viewed from the back of the scale, is shown below:
13
7 3 2 1
* * * * * * * * * * * * *
* * * * * * * * * * * *
25
14
PIN
DESCRIPTION
1
Protective Ground
2
Scale Receives Data
3
Scale Transmits Data
7
Protective Ground
It is necessary for the receive data pin of the external device to be connected to pin 3
(transmit data pin) of the scale. Likewise, the transmit data pin of the external device
must be connected to the receive data pin (pin 2) of the scale. With certain devices
such as computers with 9 pin serial ports (DB9), pins 2 and 3 must be "crossed." That
is, pins 2 and 3 of the external device should be connected to pins 3 and 2 of the
scale respectively. Cables for this purpose are generally available from computer
equipment suppliers. Computers with 25 pin serial ports (DB25) generally require
"straight" cables to the Setra scale's RS-232 port.
