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EJL-136F
Wiring Precautions
(1) Explosion proof type flowmeters are not provided
cable glands.
Refer to the part Cable connection port at detector
and converter.
(2) Connect the grounding wire (IV wire 5.5mm² or
more) to a good earth ground (100Ω or less ground
resistance). Make the wire as short as possible. Do
not use a common ground shared with other
equipment where earth current may flow. An
independent earth ground is recommended.
(3) The allowable cable lengths between the detector
and converter for the separate type flowmeter
depend on the electrical conductivity of the object
fluid. See Figure 12.
(4) DO1, DO2 , and DI use the same common terminal
(COM). This COM can not connect to other
equipments which have their own ground terminal.
(Power supply for connecting to DI or DO, etc...)
Need to wire separately.
Wiring Precautions (PROFIBUS or Modbus)
(1) For wiring path, avoid places near electrical
equipment that may cause electromagnetic
induction or electrostatic induction interference
(such as a motor, transformer and wireless
transmitter).
(2) Use a PROFIBUS-PA cable for signal cable. In
addition, make sure to use a shielded cable to
improve noise resistance. Furthermore, installation
of signal cable in metal conduit is recommended.
(3) General PROFIBUS-PA cables are designed for
indoor use where cables are not exposed to
humidity, rain, etc. When you install cables, make
sure to check the operating conditions such as the
operating temperature range of the cable by
contacting its manufacturer.
(4) When you carry out cable end treatment of
PROFIBUS-PA cable, use a dedicated cable
stripper etc. so that the core wire of the cable will
not be nicked or damaged. In addition, for cables,
be careful of allowable maximum bend diameter
etc. (Basically, do not install cables in a way cables
are twisted or bent.).
(5) Consider installing a PROFIBUS-PA arrester in
the communication path of PROFBUS-PA so that
the electromagnetic flowmeter will not be affected
by lightning etc.
(6) The electromagnetic flowmeter is not equipped
with terminating resistors. Use the terminating
resistor unit for PROFIBUS-PA or junction box, if
necessary.
12
(7) Only one PROFIBUS-PA cable goes through a
cable gland of the Electromagnetic Flowmeter.
Please use the junction box at system
configuration
.
(8) Install a terminator to flowmeter that connected
to end of Modbus network.
300
200
100
50
30
10
5
3
3
5
Conductivity (µS/cm)
Figure 12. Electrical Conductivity and
Cable Length
Meter Size
To select the meter size:
See Table 3 to 4 and find meter sizes within the
velocity of 0.3 to 32.8 ft/s (0.1 to 10m/s) for a
specified full-scale (measuring range high limit)
flow. Select one that has its full-scale velocity
between 3.0 and 10 ft/s (1 and 3m/s).
Note: Make sure the full-scale flow rate used for the
final planning stage stays within 32.8 ft/s
(10m/s) in terms of flow velocity.
Table 3. Flow rate and flow velocity (English unit)
Size
(inch)
0.328 ft/s
0.98 ft/s
1/2
0.2801
0.8403
1
0.7781
2.334
1 ½
1.992
5.975
2
3.112
9.337
3
7.967
23.90
4
12.45
37.35
Table 4. Flow rate and flow velocity (SI unit)
Size
(mm)
0.1 m/s
0.3 m/s
15
0.06362
0.1908
25
0.1767
0.5301
40
0.4523
1.357
50
0.7067
2.120
80
1.809
5.428
2.827
100
8.482
10 20 30 50 100 200
Unit: gal/min
Flow rate
3.0 ft/s
10 ft/s
32.8 ft/s
2.561
8.532
7.115
23.72
18.21
60.71
28.46
94.86
72.85
242.8
113.8
379.4
Unit: m
Flow rate
1.0 m/s
3.0 m/s
10 m/s
0.6361
1.908
1.767
5.301
4.523
13.57
7.067
21.20
18.09
54.28
84.82
28.27
28.01
77.81
199.2
311.2
796.7
1,245
3
/h
6.361
17.67
45.23
70.67
180.9
282.7
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