Using the interface, Hardware, Rs232 commands – Ohaus AS Series Electronic Balances User Manual

Page 83

USING THE INTERFACE

When the interface is installed, a short

press on the

switch will initiate a

print command. Data output is in the
format shown under the P command in the
RS232 Command Table.

When the interface is connected to a com-
puter, two way communication between
the computer and balance is possible us-
ing the commands outlined in the RS232
Command Table.

Hardware

The balance can be interfaced with other
equipment utilizing the 9-pin subminia-
ture “D” connector. The pinout and pin
connections are shown in the adjacent
illustration.

The balance will not output any data un-
less pin 5 (CTS) is held in an ON state (+3
to +15 VDC). Interfaces not utilizing the
CTS handshake may tie pin 5 to pin 6 to
defeat it.

RS232 Commands

All communication is accomplished using
standard ASCII format. Only the charac-
ters shown in the following table are ac-
knowledged by the balance. Any other
commands, control characters or spaces
are ignored.

Commands sent to the balance must be
terminated with a carriage return (CR) or
carriage return-line line feed (CRLF). For
example, a tare command should appear
as shown in the adjacent diagram. Data
output by the balance is always termi-
nated with a carriage return - line feed
(CRLF).

Field:

Length:

TARE COMMAND

TARE *

PRINT *

5VDC (50 mA max.)

Data Out (TXD)

Data In (RXD)

Tare (External signal)

Clear To Send (CTS)

Data Terminal Ready (DTR)

Ground

Request To Send (RTS)

Print (External signal)

* External PRINT and/or TARE

switches may be installed as shown
in the diagram. Momentary con-
tact switches must be used.

OFF

MODE