Hach EC1000 Instruction Manual page 78

Table 11 Current Loop Customer Connection Box
Post No.
7
8
9
10
This configuration does not provide the isolation that may be required at the computer or
printer interface. Table 9 explains the function of each of the individual jumper closures.
Table 12 RS-232C Cable Configuration
pH/ORP Meter
TB1Connection
TB1-3 (TXD)
TB1-2 (RXD)
TB1-1 (COM)
* If the lines can be disabled through hardware or software, then
this jumper is not needed.
Table 13 RS-232C Line Signal Definitions
Signal Name Description
TXD Transmitted Serial Data (Output)
RXD Received Serial Data (Input)
RTS Request To Send (Output). This signal requests permission to transmit data.
Hardware handshaking uses this signal.
CTS Clear To Send (Input). This signal indicates the equipment is ready to receive
data. Hardware handshaking uses this signal.
DSR Data Set Ready (Input). This signal indicates that the remote equipment has a
data block ready to transmit. Hardware handshaking uses this signal.
DTR Data Terminal Ready (Output). This signal indicates that the equipment has a
data block ready to transmit. Hardware handshaking uses this signal.
COM Signal Ground (Common Return)
SHLD Protective Ground used for shielding
Description Function
Current loop in (+) Data input loop, positive
Current loop in (-) Data input loop, negative
Current loop out (+) Data output loop, positive
Current loop out (-) Data output loop, negative
Host Computer/Printer
Connection
(RXD)
(TXD)
(COM)
(RTS) to (CTS)*
(DSR) to (DTR)*
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