Specifications

The immediate print output is always transmitted with a carriage return and

line feed. If the balance is set to a specific number of line feeds, these will be

transmitted with a carriage return.

The RS-232 Interface Hardware

Although Setra balances can communicate with almost any RS-232 device,

the built-in interface does not include the complete protocol. Only the

transmit and receive lines of the standard interface are used. This should

not present any interfacing problems in most applications.

The data format is: 1 start bit

8 data bits including parity

1 stop bit

10 bits per frame (framing errors ignored)

Note: The balance will transmit using the parity selected; however it does

not check the parity it receives. Use an RS-232 cable to connect the

external device to the balance, or construct one following the in-

structions below.

Connect a high quality, shielded cable with a DB9S (D-Subminiature 9 pin

female connector) using the following pinout:

12345 PIN DESCRIPTION

• • • • • 2 TXD - scale transmits data

• • • • 3 RXD - scale receives data

6789 5 GRD - signal ground

Note: “Handshake” signals, such as “Clear To Send” (CTS), are not used. The

peripheral must have a minimum buffer (15 characters).

Shielded cables must be used with this unit to ensure compliance with the

Class A FCC limits.

Computers which require handshaking need a connection between two

pins on the computer’s connector named DTR and DSR (Data Terminal

Ready and Data Set Ready). CTS may also need to be jumpered to RTS at

your computer interface (Clear To Send and Request To Send). The maxi-

mum recommended cable length is 15 meters. The cable can be longer if it

has < 2,500 pF capacitance. The load impedance of the device connected

should be between 3,000 and 7,000 ohms with no more than 2,500 pF shunt

capacitance.