Wiring; Wiring Precautions; Wiring For Output Condition - YOKOGAWA DY025 User Manual

3. WIRING

WARNING
The wiring of the vortex flowmeter must be performed
by expert engineer or skilled personnel. No operator
shall be permitted to perform procedures relating to
wiring.
CAUTION
Once all wiring is complete, check the connections
before applying power to the instrument. Improper
arrangements or wiring may cause a unit malfunction
or damage.

3.1 Wiring Precautions

Be sure to observe the following precautions when wiring:
CAUTION
• In cases where the ambient temperature
exceeds 50°C (122°F), use external heat-
resistant wiring with a maximum allowable
temperature of 70°C (158°F) or above.
• Do not connect cables outdoors in wet weather
in order to prevent damage from condensation
and to protect the insulation.
• Do not splice the cable between the flowtube
terminal and the converter if it is too short.
Replace the short cable with a cable that is the
appropriate length.
• All the cable ends must be provided with round
crimp-on terminals and be securely wired.
• Be sure to turn power off before opening the
cover.
• Before turning the power on, tighten the cover
securely.
• Explosion protected types must be wired in
accordance with specific requirement (and, in
certain countries, legal regulations) in order to
preserve the effectiveness of their explosion
protected features.
• The terminal box cover is locked by the clamp.
In case of opening the terminal box cover, use
the hexagonal wrench attached.
• Be sure to lock the cover by the clamp using
the hexagonal wrench attached after installing
the cover.

3.2 Wiring for Output Condition

Table 3.1 shows the connection method of several output
conditions.
(1) Analog Output (4 to 20 mA DC)
This converter uses the same two wires for both, the
signal and power supply. A DC power supply is required
in a transmission loop. The total leadwire resistance
including the instrument load and power distributor
(supplied by the user) must conform to a value in the
permissible load resistance range. Refer to Figure 3.1
shows.
600
R=
250
10.5
Power Supply Voltage E (V)
Figure 3.1 Relationship between Power Supply Voltage
and Load Resistance (4 to 20 mA DC Output)
(2) Pulse output and Alarm, Status Output
This version uses three wires between the converter and
the power supply. A DC power and load resistance are
required, and pulse output is connected to a totalizer or
an electric counter. Low level of the pulse output is 0
to 2V. No communication is possible over a transmis-
sion line. Communication via the amplifier board is
always possible irrespective of the wiring condition.
(3) Simultaneous Analog-Pulse Output
When using digitalYEWFLO in the simultaneous analog
-pulse output mode, the communicable distance of the
transmission line is restricted on the wiring method.
Table 3.1 shows the examples of connection for this
output mode. Communication via the amplifier board is
always possible irrespective of the wiring condition.
3-1
E–10.5
Communication
0.0236
Applicable range
BRAIN and HART
16.4 24.7 30
IM 01F06A00-01E
3. WIRING
42
F030201.EPS