Gill Instruments Ltd
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WindObserver II Page 12 Issue 18
Doc. No. 1390-PS-0004 January 2009
6.4. Connections
Important Do NOT join any of the cores of the cable together. Joining cores
could damage the unit permanently. Any cores not used should be isolated.
Do NOT connect the unit’s 0V, heating –ve, analogue output 0V or digital 0V to the
screen or earth.
The screens of each pair are joined together inside the anemometer - these should be
joined to the cable screen(s) of any further cable run. Avoid long grounding loops. Digital
OV should be used in conjunction with RS422 TX RX lines in order to improve noise
immunity. Each pair in the cable is labelled with its pair number.
Table 2
Conductor colour Designation
Pair 1 green RS422_TXB (+)
black RS422_TXA (-)
Pair 2 white RS422_RXB (+)
black RS422_RXA (-)
Pair 3 red Supply V+
black Supply V-
Pair 4 blue Digital 0v
black Analogue 0v
Pair 5 yellow Heater + *
1
black
Heater – *
1
Pair 6 brown Analogue Ch 3 output *
2
black Analogue 0v *
2
Pair 7 orange Not used (isolate) *
2
black Not used (isolate) *
2
Pair 8 white Analogue Ch 1 output *
2
red Analogue Ch 2 output *
2
Pair 9 green Not used (isolate) *
2
red Not used (isolate) *
2
Screens Chassis ground
*
1 and 2
Note may not be functional - check model number and options fitted.
*
2
NOTE Analogue connections change on units from serial number XXXXXX.
Earthing or grounding
To ensure correct operation, and for maximum protection against lightning, the
anemometer MUST be correctly earthed (grounded) via its mountings. Inadequate
Earthing will degrade anemometer performance, particularly in the presence of radio
frequency interference.
See Fig 1 Suggested mounting bracket and Earthing (grounding) arrangements
The unit MUST be connected to an appropriate grounding point with a minimum of 6mm²
copper wire, via the M5 base screws. The cable screens must be joined with any cable
screen continuing from the unit’s cable via a junction box. The primary earth for the
anemometer must be provided via the base screws and not via the cable screens.
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