Transmitter Wiring; Cable Connection - ABB LMT100 Operation Instructions Manual

L M T S E R I E S | M A G N E TO S T R I C T I V E L E V E L T R A N S M I T T E R | O I/ L M T 1 0 0/ 2 0 0 - E N R E V. B

6 Transmitter wiring

DANGER - Serious damage to health / risk to life
Observe all applicable regulations governing electrical installation Connections must be established only in a zero-voltage state
Since the transmitter does not switch-off elements, overvoltage protection devices, lightning protection and / or voltage
separation capacity must be provided at the plant (overvoltage / lightning protection is optional) Check that the existing
operating voltage corresponds to the voltage indicated on the name plate The same wires are used for both the power supply and
output signal In case the surge protection option is present and the transmitter is installed in a hazardous area, the transmitter
has to be supplied power from a voltage source isolated from mains (galvanic separation) Furthermore, the potential equalization
for the entire powering cable must be guaranteed since the intrinsic safety circuit of the transmitter is grounded
Electrical shock can result in death or serious injury Avoid contact with the leads and terminals High voltage can be present on
leads and cause electrical shock
Do NOT make electrical connections unless the electrical code designation stamped on the transmitter data plate agrees with the
area classification in which the transmitter is to be installed Failure to comply with this warning can result in fire or explosion

Cable connection

Depending on the design supplied, the electrical connection is established via a cable entry, M20 x 1 5 or ½" NPT thread The screw
terminals are suitable for wire cross sections up to 2 5 mm
IMPORTANT NOTE
With transmitters for use in "Zone 2", a qualified cable gland for this type of protection must be installed by the customer (refer the
LMT Series Safety Manual (SM LMT100200-EN A) M20 x 1 5 threads are located in the electronics housing for this purpose For
transmitters with a flame-proof enclosure (Ex d) type of protection, the housing cover must be secured using the locking screw
The screw plug that may have been supplied with the transmitter must be sealed at the plant using Molykote DX The installer
assumes responsibility for any other type of sealing medium used Increased force is required to unscrew the housing cover after
an interval of several weeks This is not caused by the threads but is due to the type of gasket
CAUTION
• The cable entry device shall comply with the requirements of EN 60079-0 and maintain IP 54 or better as required by the
installation conditions
• Field wiring should be rated at least 10°C above the device maximum ambient temperature
Figure 17 LMT HART wiring scheme
(AWG 14)
2
1
2
3
4
5
6
7
8
9
0
Internal earthing terminal
Power supply, current output / HART output
Load resistance
Power supply / supply isolator
PLC / DCS
HART Handheld terminal
External indicator
External earthing terminal
Terminal for external indicator
Laptop
19