3KP78 - 2.2
3000PLUS
WITH
5D78 I
NSTRUCTION
M
ANUAL V
. SB.3
2. C
ONNECTIONS
tor software will automatically set to this protocol the
computer COM PORT selected for communications
with the 3000PLUS (see “Setup and Testing of Serial
Communications” in the Configurator’s on-line HELP
system).
Separate shielding of the RECEIVE and TRANSMIT lines
is highly recommended, especially if the cable connect-
ing the PC and the 3000PLUS is over three feet in
length. This will prevent electrical noise from causing
“break” signals and other communications errors.
As shown in Fig. 7, simple two-wire RS232 cabling is
employed for communications between the 3000PLUS
and an external PC. While 3000PLUS / PC serial com-
munications will usually take place through the 3KP
Configurator software described in Section 4, a “termi-
nal emulation” program (either conventional or cus-
tomized) can also be used to issue standard mnemonic
commands to the meter, and to receive meter respons-
es.
The RS232 interface observes a fixed protocol of
19,200 baud, 8 data bits, 1 stop bit, and NO parity—with
no software or hardware “handshake.” The Configura-
2.
B
S
ERIAL
C
OMMUNICATIONS
C
ONNECTIONS
AAAA
AAAA
AAAA
A
/
D
COM
OUT
COM
A
/
D
INP
V
OUT
4-20
OUT
LOG
COM
HLD
PEK
TAR
LOG
COM
RCV
XMT
PWR
COM
+24
VDC
HI
HI
LO
LO
OK
OK
HAV
PEK
RLS
LAT
COM
PORT
AA
AA
AA
AA
AA
AA
AA
AA
AA
PC for
Configuration /
Data Acquisition
RECEIVE
TRANSMIT
COMMON
SHIELD
Fig. 7
RS232 Interface Connections
