Caution – Yokogawa DR240 User Manual
Page 61
3-16
IM DR232-01E
Connecting the RS-232-C cable
For details on connecting the RS-232-C connector of the RS-232-C communication interface
module to a personal computer, see IM DR231-11E, “DR231/DR232/DR241/DR242
Communication Interface User’s Manual.”
CAUTION
When (dis)connecting the RS-232-C cable, turn OFF the power of both
the personal computer and the instrument. If the power is not turned
OFF, malfunctions may occur and the internal circuitry may be
damaged.
Note
To reduce noise, use ferrite cores (e.g., ZCAT 3035-1330 from TDK) for the interface cable as shown
below. Two ferrite cores should be installed near both ends of the interface cable. If the noise is
particularly bad, use several ferrite cores in series. Use a shielded cable for the interface cable and make a
one-point grounding at the ground terminal of this instrument together with the functional-ground terminal
of the personal computer.
Personal
computer
Ferrite core
Function
grounding
terminal
RS-422-A/RS-485
1
2
3
4
SW1
Data length
Baud rate
ON
OFF
1
2
3
4
SW2
four-wire/two-wire
Stop bit
Parity
ON
OFF
1
2
3
4
SW3
Address (upper)
Minimum response time
ON
OFF
1
2
3
4
SW4
Address (lower)
ON
OFF
Baud rate (No.1 to 3 of SW1)
Baud rate
No.1
No.2
No.3
300
OFF
OFF
ON
600
OFF
ON
OFF
1200
OFF
ON
ON
2400
ON
OFF
OFF
4800
ON
OFF
ON
9600
ON
ON
OFF
←Default Setting
19200
ON
ON
ON
38400
OFF
OFF
OFF
Data length (No.4 of SW1)
Data length
No.4
7
OFF
8
ON
←Default Setting
3.5 Connecting the Interface Cables