User's Manual

Table Of Contents
7ML19985JE03 SITRANS LR250 (HART) INSTRUCTION MANUAL Page 25
mmmmm
Wiring
Connecting HART
1)2)
Wiring setups for hazardous area installations
There are five wiring options for hazardous area installations:
Intrinsically Safe wiring
on page 26
Non-incendive wiring (US/Canada only)
on page 28
Flameproof wiring
on page 28
Increased safety wiring
on page 29
Explosion-proof wiring (US/Canada only)
on page 29
In all cases, check the nameplate on your instrument, and confirm the approval rating.
1)
Depending on the system design, the power supply may be separate from the
PLC, or integral to it.
2)
HART resistance (total loop resistance, that is, cable resistance plus 250 Ohm
[resistor]) must be limited according to the allowable operating area as shown in
either
Curve 1 (General Purpose, Intrinsically Safe, Non-incendive)
on page 140
or
Curve 2 (Flameproof, Increased Safety, Explosion-proof)
on page 141.
active PLC
HART modem
SITRANS LR250
power supply
(1)
Typical PLC/mA configuration with HART
R= 250
(2)
HART
communicator