Yokogawa EJA530A - Manual (Page 27)

IM 01C21F01-01E 6-3
6. WIRING
(2) Flameproof Type
Wire cables through a flameproof packing adapter, or
using a flameproof metal conduit.
᭿ Wiring cable through flameproof packing adapter.
• Apply a nonhardening sealant to the terminal box
connection port and to the threads on the flameproof
packing adapter for waterproofing.
F0608.EPS
Flameproof packing adapter
Flexible metal conduit
Wiring metal
conduit
Tee
Drain plug
Apply a non-hardening
sealant to the threads for
waterproofing.
Figure 6.4.2b Typical Cable Wiring Using Flameproof
Packing Adapter
᭿ Flameproof metal conduit wiring
• A seal fitting must be installed near the terminal box
connection port for a sealed construction.
• Apply a non-hardening sealant to the threads of the
terminal box connection port, flexible metal conduit
and seal fitting for waterproofing.
F0609.EPS
Non-hazardous area
Hazardous area
Flameproof
heavy-gauge
steel conduit
Tee
Drain plug
Seal fitting
Gas sealing device
Flameproof flexible
metal conduit
Apply a non-hardening
sealant to the threads of
these fittings for
waterproofing
After wiring, impregnate the fitting
with a compound to seal tubing.
Figure 6.4.2c Typical Wiring Using Flameproof Metal
Conduit
6.5 Grounding
Grounding is always required for the proper operation
of transmitters. Follow the domestic electrical require-
ments as regulated in each country. For a transmitter
with built-in lightning protector, grounding should
satisfy ground resistance of 10
⍀ or less.
Ground terminals are located on the inside and outside
of the terminal box. Either of these terminals may be
used.
Ground terminal
(Inside)
Ground terminal
(Outside)
Transmitter terminal box
F0610.EPS
Figure 6.5 Ground Terminals
6.6 Power Supply Voltage and
Load Resistance
When configuring the loop, make sure that the external
load resistance is within the range in the figure below.
(Note) In case of an intrinsically safe transmitter, external load
resistance includes safety barrier resistance.
;;
600
250
0 10.5 16.4 24.7 42
External
load
resistance
R ( Ω)
Power supply voltage E (V DC)
F0611.EPS
Communication
applicable range
BRAIN and HART
R=
E–10.5
0.0236
Figure 6.6 Relationship between Power Supply Voltage
and External Load Resistance