Yokogawa JUXTA VJA7 - Manual (Page 2)

2
All Rights Reserved. Copyright © 1999, Yokogawa M&C Corporation IM 77J01A07-01E 3rd Edition Mar.31,1997-00
4.3 Mounting Using a Multi-mounting Base
For mounting using a multi-mounting base, see the Instruction
Manual for VJCE (VJ Mounting Base).
4.4 Using Ducts
Wiring ducts should be installed at least 30 mm away from the top
or bottom of the main unit.
4.5 In case of top-and-bottom close mounting
Transmitter should be mounted horizontally with its top and bot-
tom slits being vertical. The top and bottom slits should not be
covered.
The area for wiring is required above and below the transmitter
(the area with slant lines).
ALM1
ALM2
ALM1
ALM2
ALM1
ALM2
ALM1
ALM2
ALM1
ALM2
ALM1
ALM2
(29.5)
29.5 or more
40 or more
40 or more
(72)
(72)
78 or more
150 or more
Fig. 4.3
5. INSTALLATION LOCATION
• For installation, avoid any location where the product may be
subject to vibrations, corrosive gases, or large amounts of
dust, or where the product is exposed to water, oil, solvents,
direct sunlight, radioactive rays, or strong electric or magnetic
fields.
• If there is a possibility that lightening could induce a high
surge voltage on the power and signal lines, provide lighten-
ing arresters on the line between the field instrument and in-
door instrument in order to protect the product. Install a dedi-
cated arrester on the field side and another on the indoor side.
6. EXTERNAL WIRING
WARNING
Turn OFF the power supply and make sure that none of the
cables are not in the hot-line state before carrying out the
wiring to avoid the possibility of electric shock.
Wires are connected to the terminals of the distributor’s socket. M3
screw terminals are provided for the connection of external signals.
Attach a crimp-on lug to each wire for connection to the terminals.
• Recommended cables: A nominal cross-sectional area of 0.5
mm
2 or thicker for signal cables, and that of 1.25 mm 2 or
thicker for power cables, and shielded twisted-pair cables
(AWG24) for communication wiring cables.
• For mounting, use M3 screws and crimp-on terminals with in-
sulating sleeves appropriate for the wires used.
Tool of the crimp-on terminals to be used should be appropri-
ate for the crimp-on terminals.
• Mount a breaker on the external place.
Mount a switch or 5A circuit breaker on the place near by the
instrument, within operator’s reach. And attach the indication
that it is for disconnecting the instrument.
3
1
4
5
2
6
3
1
3
1
4 4
PS+
- -
When internal
power is used When external
power is used
Example of using
a Zener barrier to
configure an
intrinsically safe
system
Input signal
9
7
+
-
Analog output
Output-1 signal
5
2
+
-
Analog output
Output-2 signal
ALM1
ALM2
COM
Alarm output
5
2
6
B+
A-
COM
RS-485
communication
11
10
8
L+
N-
GND
Power Supply
+
+
COM COM COM
-
- -
PS+
+
-
10 11
3 2 1
4 5 6
7 8 9
Fig. 6.1
NOTE
● Keep all sources of noise away from the power and sig-
nal cables. Otherwise, accuracy cannot be assured.
● Provide grounding to a grounding resistance of 100 ⍀.
The length of the grounding cable should be 20 m or
less. Directly connect the lead from the ground terminal
(terminal no. 8) of the distributor to the ground. Do not
carry out daisy-chained inter-ground terminal wiring.
● Direct Current
● “Overvoltage category (Installation category)” describes
a number which defines a transient overvoltage condi-
tion. It implies the regulation for impulse withstand volt-
age. “II” applies to electrical equipment which is sup-
plied from the fixed installation like distribution board.
● “Pollution degree” describes the degree to which a solid,
liquid, or gas which deteriorates dielectric strength or
surface resistivity is adhering. “2” applies to normal in-
door atmosphere. Normally, only non-conductive pollu-
tion occurs. Occasionally, however, temporary conduc-
tivity caused by condensation must be expected.
● Rated fuse of 125VDC, 1A is stored. However, opera-
tors can not replace the fuse.