Skipper DL2 - Yard Supplied Extension Cable from Sensor to JB70 Electronic Unit; The Junction Box (Jb12);Splice

2018-05-28
Page 23 of 60
Installation DL2 Doppler Speed Log System
The JuncTiOn bOx (Jb12)/splice
The JB12 Junction box may be used as a terminal between sensor cable and an extension cable.
Dimensional drawing see Appendix 1.
All individual screens of sensor cable to be connected to the outer screen of the CAT7 extension
cable.
Do not ground screens to JB12 chassis.
yard supplied exTensiOn cable frOm sensOr TO Jb70 elecTrOnic uniT.
Any screened 3 or 4 twisted pair cable can be used as long as the loop resistance (measured by
twisting the pair together at one end and measuring the resistance) is less than 8.6 ohms (worst
case).
Example1:
What kind of cable do I need for 300m distance from sensor to Electronic unit?
300m cable (0.3km). Loop length 0.3*2 =0.6km. 8.6/0.6=14.3 Ohms/km
Use a cable with maximum 60 Ohm conductor DC resistance per km.
AWG15 / 1.5mms has resistance of 10.4 ohm /km
Example2
I have a CAT7 cable. Spec says 70 Ohm conductor DC resistance per km. How long distance from
sensor to Electronic unit can I use this cable?
8.6/70=0.122km. 0.122km/2=60.1m maximum length.
Color Code Signal Screen Color Code Pair Screen
White +18-36 V DC
Individually
screened pair
Brown / White (blue) Pair
Common screen
Black 0 V Blue (brown) / Blue (white) Pair
Yellow TX+
Individually
screened pair
White (green)
Pair
Black TX- Green (white)
White RX+
Individually
screened pair
White (orange)
Pair
Orange RX- Orange (white)
Yellow Aux+
Individually
screened pair
N/A
Pair
Orange Aux- N/A
To be grounded
together and
passed into the
outer screen of the
Cat5e cable