Northern Airborne Technology AA36-002 - Manual (Page 10)

AA36-ECF Tie Line Manual SM42 Rev. 4.00
2.3.2 Cautions
⇒ In all installations, use shielded cable exactly as shown and ground as indicated.
Significant ground loop and noise problems may result from not following these
guidelines.
⇒
Use caution when routing ICS tie line wiring as they use low level signals and are
prone to coupling from other sources.
Do not take a ground from the front panel or similar location that shares a ground return
with a turn and bank, horizon or other motor driven instrument. This may cause the unit
to pick up the sound of the motor as ground loop interference.
2.3.3
Cabling and Wiring
All unshielded wire should be MIL-W-22759 or equivalent. For shielded wire
applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves (for shield
terminations) to make the most compact and easily terminated interconnect. Follow the
wiring diagrams in Section 2.6 as required.
Allow 3 inches from the end of the wire to the shield termination to allow the hood to be
easily installed. Note that the hood is a ‘clamshell’ hood, and is installed after the wiring
is complete.
All wiring should be at least 22 AWG, except power and ground lines, which should be
at least 20 AWG. Ensure that all ground connections are clean and well secured.
To prevent system failure or inadequate equipment protection, supply power from a
separate 1.0 A breaker or fuse, not connected to any other source.
2.3.4 Setting NAT ICS TIE Output
The mic signal from the Audio Controller to the AA36-ECF ICS IN is expected to be
approximately 500 mVrms.
The INPUT ADJ trimpot is factory set to provide 340 mV RMS
± 10% on the NAT ICS
TIE line, but can be adjusted to give the desired output.
2.3.5
Setting ICS OUT
The signal level measured on the ICS tie line from the NAT audio controller/intercom
system is typically 340 mVrms, which is fed into the NAT ICS TIE on the AA36-ECF.
The OUTPUT ADJ trimpot on the AA36-ECF is factory set to provide 500 mVrms
± 10%
signal at ICS OUT, measured across a 5 kOhm load, but can be adjusted to give the
desired output.
Page 2-2 Dec 5, 2003
ENG-FORM: 805-0106.DOT
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