Yokogawa EJA110A - Manual (Page 31)

IM 01C21B01-01E 6-2
6. WIRING
6.3.4 Check Meter Connection
Connect the check meter to the CHECK + and –
terminals (use hooks).
• A 4 to 20 mA DC output signal from the CHECK +
and – terminals.
(Note) Use a check meter whose internal resistance is 10
Ω
or less.
Transmitter terminal box
F0604.EPS
Power supply
–
+
Check meter
Figure 6.3.4 Check Meter Connection
6.4 Wiring
6.4.1 Loop Configuration
Since the DPharp uses a two-wire transmission system,
signal wiring is also used as power wiring.
DC power is required for the transmitter loop. The
transmitter and distributor are connected as shown
below.
For details of the power supply voltage and load
resistance, see Section 6.6; for communications line
requirements, see Subsection 8.1.2.
(1) General-use Type and Flameproof Type
Hazardous Location Nonhazardous Location
Transmitter terminal box
Distributor
(Power supply unit)
Receiver
instrument
F0605.EPS
–
+
Figure 6.4.1a Connection between Transmitter and
Distributor
(2) Intrinsically Safe Type
For intrinsically safe type, a safety barrier must be
included in the loop.
Hazardous Location Nonhazardous Location
Transmitter terminal box
Distributor
(Power supply unit)
Receiver
instrument
Safety barrier
F0606.EPS
–
+
Figure 6.4.1b Connection between Transmitter and
Distributor
6.4.2 Wiring Installation
(1) General-use Type and Intrinsically Safe
Type
Make cable wiring using metallic conduit or water-
proof glands.
• Apply a non-hardening sealant to the terminal box
connection port and to the threads on the flexible
metal conduit for waterproofing.
F0607.EPS
Flexible metal conduit
Wiring metal
conduit
Tee
Drain plug
Apply a non-hardening
sealant to the threads for
waterproofing.
Figure 6.4.2a Typical Wiring Using Flexible Metal Conduit