Yokogawa digitalYEWFLO (DY) - Manual (Page 45)

INSTALLATION
IM 1F2B4-01-YIA
Page 49
b) Slide another heat shrinkable tubing
over the wire bundle such that it covers
the inner braided shield, overlaps the
inner jacket and the loose wires A, B,
and C as shown. Be certain that the heat
shrink tubing protects all shield wires
from chassis ground. Heat the tubing as
necessary to shrink it for a tight fit.
7. Install insulated crimp lugs on each wire A, B, C and G.
8. Attach identifying labels to the outside of each signal cable.
Confirm that the insulation between each wire including the inner shield is 10 Mega Ohm or greater
at 500 VDC. Maintain both ends of the wires disconnected (open circuit) during insulation resistance
(Hi-Pot) test.
3.5 W
IRING
C
AUTIONS
When installing the YEWFLO in a hazardous area, particular care must be taken when wiring the
meter not violate any of the requirements of the hazardous area approvals.
For explosionproof installations, the wiring must be protected by conduit and proper seals so
hazardous material exposure is limited and consistent with the requirements of the approving agency
(FM or CSA). If you are unsure about the requirements of the approving agency, consult their
appropriate standards handbook.
3.5.1 Flameproof transmitter installation
The model YF100 vortex flowmeters and YFA11 vortex flow converters are designed to be used in
hazardous areas, divisions 1 and 2. Their specific uses are outlined in “Recommended practice for
explosion-protected electrical installations in general industries (Gas Explosion Protection, 1985).”
To avoid damaging the flameproof equipment, connecting bolts, wiring and pipes should be installed
with care. Caution should also be used for maintenance and repair of the equipment. For further
information, refer to “Operating precautions for instruments of flameproof construction conforming
to technical criteria (IEC-Compatible Standards)”
3.5.2 Cautions for insulation and dielectric strength testing
Since the flowmeter has undergone insulation and dielectric tests at the factory prior to shipment,
these tests are normally not required again. However, if required, follow the precautions and
procedures listed below:
1)
Do not apply voltages exceeding 500 VDC for insulation resistance testing or 500 VAC for
dielectric strength testing.
2) Before conducting these tests, disconnect signal lines from the flowmeter terminals.
•Insulation Resistance Test Procedure
1)
Short-circuit the + and – (4-20 mA output type) or +, P and – (pulse output type) terminals in
the terminal box.