Wiring Setups For Hazardous Area Installations - Siemens 7ML5431 Operating Instructions Manual

Connecting

5.3 Wiring setups for hazardous area installations

Connecting HART
Typical PLC/mA configuration with HART
①
②
③
Note
• Depending on the system design, the power supply may be separate from the PLC, or
integral to it.
• 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
(Page 257) (General Purpose, Intrinsically Safe, Non-Sparking, Non-incendive) or Curve
2 (Page 257) (Flameproof, Increased Safety, Explosion-proof).
5.3 Wiring setups for hazardous area installations
There are six wiring options for hazardous area installations:
● Intrinsically Safe wiring (Page 43)
● Non-Sparking wiring (Page 44)
● Non-incendive wiring (US/Canada only) (Page 45)
● Flameproof wiring (Page 45)
● Increased safety wiring (Page 46)
● Explosion-proof wiring (US/Canada only) (Page 46)
In all cases, check the nameplate on your instrument, confirm the approval rating, and
perform installation and wiring according to your local safety codes.
42
④
Power supply
⑤
SITRANS LR250
⑥
R = 250 Ω
Active PLC
HART modem
HART communicator
Operating Instructions, 10/2019, A5E32220602-AG
SITRANS LR250 with mA/HART