Gill Instruments Ltd
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MetPak/MetPak RG and MetPak Pro Base Stations
Page | 22
Issue 1
Doc. No. 1723-PS-0023
October 2018
4.4.
Cable Connections General
Any cable wires not used should be isolated and grounded at the terminating equipment/user end.
Digital OV should be used in conjunction with RS422 TX/RX lines in order to improve noise
immunity.
The Cable should be secured:-
With cable clamps or equivalent at regular intervals such that the hub box cable gland
does not support the cable weight.
Away from the mounting bolts to prevent chaffing of the cable.
NOTES:-
Install appropriate strain relief support to the cable. If possible, pass the cable through the
mounting pole.
The Base Station unit Hub Box cable glands contain spring loaded metal leaves that are designed
to make a ground contact with cables that have an overall braid screen. Care is therefore required
when inserting and removing cables through the glands to prevent damage to the metal leaves.
4.5.
Earthing
To ensure correct operation and for maximum protection from lightning, a separate lightning rod
system is recommended to protect the system.
You can also earth the Base Station through its mountings or by connecting a grounding cable
(minimum of 6mm² copper wire) to a spare Base Station metalwork bolt hole. Clean off any paint
that might prevent a good connection.
When you connect the communications cable ensure that the screen has a connection to the hub
box case.
The Junction Box accessory has a plastic case, hence ensure continuity of cable screens into and
out of the Junction Box using the common Earthing terminals provided in the box.
4.6.
Power Supplies
Supply Voltage:
12v to 30v DC.
Average Current at 12v dc:-
MetPak Base Station
15mA plus external wind sensor current
MetPak RG Base Station
23mA plus external wind sensor current.
MetPak Pro Base Station
23mA plus external wind sensor current and any
Analogue 1/2 current connected units.
Base Station Units have reverse voltage polarity protection.
