Yokogawa digitalYEWFLO (DY) - Manual (Page 20)

<4. WIRING>
4-1
IM 01F06A00-01EN
4. WIRING
WARNING
The wiring of the vortex fl owmeter 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.
4.1 Load Resistance of Output
Condition
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 fl owtube
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 specifi c 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
Locking Screw. In case of opening the
terminal box cover, use the hexagonal
wrench attached.
• Be sure to lock the cover by the Locking
Screw using the hexagonal wrench attached
after installing the cover.
Table 4.1 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 4.1.