Siemens Sitrans LR400 Instruction Manual page 22

Connecting the SITRANS LR400:
1. Release the cover lock on the connection box with a 3 mm Allen key.
2. Unscrew the cover from the connection box.
3. Push the power cable and signal cable through the cable gland on the right of the
unit, up to the terminal strip. Lay the cable in a bend before the cable gland so that
moisture cannot enter the connection box.
4. Connect the earth conductor of the power supply to the earth terminal
connection box. Adjust the cable length so that the earth conductor would be last to
disconnect last if cable is pulled.
5. In devices with ignition protection types II 1/2G EEx dem [ia] IIC T6 and II 1/2G EEx
dem [ib] IIC T6 or II 2G EEx dem [ia] IIC T6 and II 2G EEx dem [ib] IIC T6 (7ML5421
version), mount the cover for the power supply terminals.
6. Tighten the cable screw gland and check the strain relief (pull and turn).
7. In devices with ignition protection type II 1/2G EEx D IIC T6 or II 2G EEx d IIC T6
(7ML5421 version), replace unused screw-type cable glands with a certified dummy
plug.
8. Screw the cover onto the housing and tighten it without using a tool. The sealing
ring must be clean and undamaged.
9. Mount the cover lock of the connection box cover.
10. Connect the earth terminal located between the screw-type cable glands to a
ground connection at your vessel by using a cable of a cross-section at least
2
2.5 mm .
For error-free communication via the HART protocol, a load of at least 230 Ω must be
available in the signal circuit.
WARNINGS:
• To avoid short-circuits, do not connect a load resistance with bare wires in
the connection box.
• The housing cover may not be unscrewed in a hazardous area when the
device is under voltage (power supply, digital outputs on external supply).
• In devices with ignition protection types II 1/2G EEx dem [ia] IIC T6 and II 1/
2G EEx dem [ib] IIC T6 II 2G EEx dem [ia] IIC T6 and II 2G EEx dem [ib]
IIC T6 (7ML5421 version), only the cover of the connection box may be
unscrewed for test purposes. The cover on the power supply terminals may
not be removed!
Page 18 SITRANS LR400 (7ML5421) – INSTRUCTION MANUAL
in the
7ML19985FH06