AFDAU-T1 Aerial Firefighting
Data Acquisition Unit
Installation Manual
AMS-IM-1-01 Rev. 7
22 September 2021
12
2.2.3 Container Door Open
For the AFDAU-T1 to send drop start and drop stop event messages to the connected modem, the AFDAU-T1 must
be connected to a discrete signal that is active when the pilot commands the door or valve to open on the hopper, tank
or bucket.
The AFDAU-T1 can be configured for a discrete switched signal that represents the container open door state of the
container on one of either the 6 Relays or the 6 GPI inputs.
This input can be either momentary, such as pressing a release trigger, or on for the duration of the drop such as a
microswitch fitted to a hopper door.
Helicopter Tank Typical Connections
•
Helitak Tank PLC: No analog connection required. This signal is supplied to the AFDAU-T1 via the Helitak
Tank RS-232 protocol.
Helicopter Bucket Typical Connections
•
Waterhog Buckets: Typically, this would be connected to the door open side of the
pilot’s trigger switch.
•
Bambi Max, Bambi Buckets: Typically, this would be connected to the switched side of the release switch.
•
Dual Bucket Circuits: When an aircraft features more than one bucket control circuits (i.e both Bambi and
Waterhog Bucket control circuits) both systems need to be detected by the Bucket Door Open input.
Appropriate isolation needs to be insured when implementing this such as installing an additional relay.
CAUTION
NEVER CONNECT BUCKET SYSTEM DROP SIGNAL WIRING DIRECTLY TOGETHER.
PROPER ISOLATION BETWEEN THE TWO SYSTEMS MUST BE IMPLEMENTED.
Fixed-Wing Hopper Typical Connections:
A door open discrete signal via a micro switch is the preferred method for detecting door open command with the
AFDAU-T1. Consideration to suitability should be given if intending to connect to an electronic drop circuit that may
not be used if the manual release is used for a time.
2.2.4
NOTE
This connection is not required when only interfacing to a Helitak Tank PLC. This data is
supplied via the Helitak Tank RS-232 protocol. For all other installations including a dual
Helitak tank and bucket installation, connection is required.
