Table of Contents
Advertisement
Installation hints for best performance
This section offers several suggestions which will help you get the best performance from
your measurement system.
Some sensors generate comparitively small signals which can easily be corrupted by the
potentially high level of electrical noise which can be created by electrical machinery such as
motors, welding systems, discharge lighting, AC power inverters and solenoids. These steps
will ensure you get the best possible performance from your system.
1.
Use good quality screened signal cable, with twisted pairs. Belden 8777NH,
Belden 9503 and AlphaWire 6010C are good choices, available from many
electrical distributors.
2.
If you are using multi-pair twisted cable, each pair should be dedicated to a single
display as shown opposite, for maximum noise immunity.This will ensure that any
electrical noise induced in the cable is properly cancelled. Mixing destinations
carelessly amongst the twisted pairs can actually worsen noise performance.
3.
The cable should be routed away from noisy wiring and devices such as power
feeds from inverters, discharge-lighting cables, welder cabling etc, and should
preferrably be routed in a dedicated low voltage signalling/instrumentation conduit
or cable tray.
4.
Screened cable should be earthed at the display end only.
5.
All wires and screens coming out of the screened cable should be kept as short
as possible to minimise pickup of noise.
6.
If you are using barriers, you should earth your screen as shown below, paying
particular care that you do not earth both ends of any run of of cable.
Sensor
Length of screened cable
Do not
connect
screen at
this end.
Sensor connections
12
Hazardous Area
Barriers
Connect screen
to earth ONLY
at this end.
Barrier connections
Safe Area
Length of screened cable
Do not
Connect screen
connect
to earth ONLY
screen at
at this end.
this end.
Terminal 7
on logic
input
connector
Clean Earth
Display connections
Advertisement
Table of Contents
