Vaisala HMP240 User Manual
Page 15
HMP240 series
M210300en
User's Guide
13
3.3
Grounding
A single electrical cable with a screen and three to ten wires is recommended
for power and analogue output/serial bus connections. The cable diameter
should be 7...10 mm.
The screen of the electrical cable must be grounded properly to achieve best
possible EMC performance. Recommended cable shield is done in the cable
gland as shown below.
•
remove the brass disks, rubber ring and nut from the transmitter
housing
•
strip 165 mm of the cable insulation, but leave 25 mm of the braid
visible
•
slip the nut and rubber ring over the cable insulation
•
slip the brass disk that has the bigger hole in it over the braid so that
it rests against the cable insulation
•
slip the other brass disk over the wires to the middle of the braid
(If the cable diameter is less
than 7mm, use a shrinking
tube or an adhesive tape)
cable
braid
flexible wires 0.5 mm
(AWG 20), stranded wires
recommended
2
D = Ø 7...10 mm
3
brass
disks
25
rubber
ring
nut
brass disks
140
165
shielding tube
braid
•
push back the braid and press it between the two brass disks to
achieve a full 360° grounding; the fold between the disks should have
the same diameter as the brass disks
•
secure the braid with a shielding tube
•
insert the wires into the transmitter housing through the gland