User's Manual

Table Of Contents
Connecting
5.2 Connecting SITRANS LR250
SITRANS LR250 (HART)
Operating Instructions, 01/2014, A5E32220602-AB
27
Wiring instructions
1. Strip the cable jacket for approximately 70 mm (2.75") from the end of the cable, and thread
the wires through the gland. (If cable is routed through conduit, use only approved suitable-
size hubs for waterproof applications.)
2. Connect the wires to the terminals as shown: the polarity is identified on the terminal block.
3. Ground the device according to local regulations.
4. Tighten the gland to form a good seal.
5. Close the lid and secure the locking screw before programming and device configuration.
Connecting HART
Typical PLC/mA configuration with HART
Power supply
Active PLC
SITRANS LR250
HART modem
R = 250 Ω
HART communicator
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 237) (General Purpose, Intrinsically Safe, Non-Sparking, Non-incendive) or Curve
2 (Page 238) (Flameproof, Increased Safety, Explosion-proof).