Remote Programming - Omega DPF700 User Manual

8
RS-232 O

8.2 REMOTE PROGRAMMING

The meter may accept an RS-232 card for communications. The card enables the meter to
receive setup commands and data, and send measurement values and current setup data to a
computer. The meter operates at either 1200 or 9600 baud, 7 data bits, even parity and 1 stop
bit. It emulates DCE (data communication equipment) and uses a handshake line while sending
data, but none while receiving data. A 4-wire cable is the maximum required for the following
communications:
When you connect your meter to a computer, such as an IBM PC, and the meter receives one of
8 commands (P, G, W, R, V, SC, SG and SP) the meter interrupts its program, receives the
message, takes appropriate action, and then starts over with a new measurement. No hand-
shake is required because the meter devotes its full attention to receiving the command data
from the computer. In the other direction, the meter sends measurement and confirming setup
data to the computer under one of 2 handshake (RTS) modes.
Message Handshake - The RTS line is checked when the device is ready to send
measurement data. If the RTS is true, it sends the complete message data without interruption
even if the RTS goes false in the middle of transmission. If the RTS is false, it skips sending the
data completely and continues with the next measurement.
Character Handshake - The device checks the RTS input before sending each character
and sends characters only while the RTS is true.
34
PTION
Signal return (RTN)
Received data (RX)
Transmitted data (TX)
Request to send (RTS)
6
N/C
5
4
3
2
1
N/C