•
With power applied and switch settings in the desired positions, press the reset
button.
•
Observe the detection of vehicles by watching the front panel detect LED.
Loop installation:
The Northstar NT11 and NT11-E detectors will operate with loop and lead-in’s whose
total inductance is between 20µH and 2000µH. Loops with a perimeter less than 30 feet
should have at least three turns, between 30 feet and 120 feet should have two turns and
over 120 feet should have one turn of wire.
Loop and lead-in should be proper loop wire, #12 or #14 AWG, lead-in should be twisted
at least seven twists per foot. Shielded lead-in’s are not essential but are recommended
especially on longer runs. Loop and lead-in should have an insulation resistance to
ground greater than 50M
Ω
measured at 500V and a series resistance of less than 10
Ω
.
Loop size and location are a function of application and are dictated by experience.
Northstar detectors will handle a wide range of loop and lead-in systems.
Adjustments
– NT11 and NT11-E
Sensitivity: Four front panel DIP switches provide for 16 sensitivity settings
.
Setting Level dL/L Setting Level dL/L Setting Level dL/L
15 .01% 10 .06% 5 .32%
14 .015% 9 .08% 4 .48%
13 .02% 8 .12% 3 .64%
12 .03% 7 .16% 2 .96%
11 .04% 6 .24% 1 1.28%
0
2.56%
* see chart on page 6 for DIP positions
Frequency: Two front panel DIP switches provide for 4 frequency settings.
•
F2+F1 = High
•
F2+F0 = Medium High
•
F1+F0 = Medium Low
•
F0+F0 = Low
Page 4
Summary of Contents for NT11
Page 10: ......
