Microair Avionics EC2002 Altitude Encoder

About This Document
This manual describes the installation of the Microair EC2002 altitude encoder. Microair has supplied additional information to enable the EC2002 to be installed with a variety of transponders.
The manual is a restricted document, and may not be amended, copied, or distributed, without the written permission of Microair Avionics. © Microair Avionics Pty Ltd.

CURRENT REVISION STATUS

01R7-2
01R7| 07/09/08| Changed reference to maximum altitude to 38,000ft
01R8| 24/11/08| 3 view drawing updated
01R9| 07/01/09| Weight data added
01R10| 25/02/09| Limited Warranty Updated
01R11| 24/04/09| repair@microair.com.au – email change
01R12| 16/04/10| Microair altitude data format amended to add CRC
01R13| 17/02/14| Removed all reference to user field calibration
01R14| 25/07/14| Removed reference to internal switch settings

INTRODUCTION

This manual describes the performance specification, installation methods, and calibration procedures of the EC2002 Altitude Encoder.

ATSO Approval
Pending.

RTCA Compliance

• The EC2002 hardware development is compliant with RTCA/DO-254 level C.
• The EC2002 software development is compliant with RTCA/DO-178B level C.
• The EC2002 is compliant with DO-160D for the following: [(A1)(D1)X]CAB[SRU]XXXXXXABABA[UU]Z[XXXX]XXX.

DESCRIPTION

The EC2002 is housed in a 1mm black anodized case, with a mounting flange at each side.

Fitted to one end of the case are a DB15 male connector for all electrical connections and a female 1/8” NPT fitting for connection to the aircraft’s static air pressure system. At the opposite end is the nameplate showing the compliance statements, the part number, serial number, and mod status.

The top of the case is fitted with a label that has the pin assignments for the DB-15 connector and clearly identifies the NPT fitting.

The EC2002 is fitted with a sensitive pressure transducer to sense the air pressure present at the NPT fitting. The transducer output is “digitized” into a numerical value and outputted as an altitude via the 10-line Gillham interface and simultaneously to the serial data interface. The EC2002 will typically start outputting altitude data 10 seconds after being turned on. The working altitude range is between -1000 feet and +35,000 feet.

The EC2002 is temperature controlled to ensure the pressure transducer is at nominal temperature, in an ambient temperature range of -20 to +55 degrees C. A heater element maintains the pressure transducer core temperature within operational specifications. Power consumption with the heater element off is 10mA and a maximum of 100mA @ 14V or 200mA @ 28V with the heater element on. The heater will be fully off when ambient air temperatures are above 15 degrees C.

IMPORTANT NOTE
The EC2002 will cease outputting altitude data if:

1. The pressure altitude goes above 35,000 feet
2. The pressure altitude drops below -1000 feet
3. The sensor temperature is not within the operational range

INSTALLATION

Microair Avionics recommends that the EC2002 be typically positioned on the firewall behind the instrument panel. If this position is not possible, the EC2002 can be attached to any flat surface, or purpose-made bracket, and retained with 3mm (1/8”) hardware via the holes (8) in the mounting plate. The EC2002 should be supported by a minimum of two points on the mounting flanges.

IMPORTANT NOTE
No additional holes are to be drilled into the case for the purpose of mounting.

Microair recommends that the installer should consider the fact that the encoder may have to be dismounted to allow for recalibration periodically. The retaining hardware should be easy to remove, or the HIGH and LOW keyholes should be accessible in the installed position.

Physical Requirements
The EC2002 may be installed in either a pressurized or non-pressurized cabin. The EC2002 should however ideally be located:

• In an area where the temperature can be reasonably controlled
• Away from cold air vents
• Away from heater elements or hot air vents
• Away from coaxial cables

Microair recommends that the EC2002 and the aircraft’s altimeter be the first two items plumbed on to the static line. This will make isolating the rest of the aircraft easy to do when the system requires a calibration check.

After installing, remove the dust plug from the NPT fitting, and connect the static hose line ensuring the NPT connector is sealed using thread tape or an appropriate sealer (not silicone). Connect the wiring harness terminated with a DB-15 from the transponder, to the DB-15 fitting adjacent to the NPT fitting on the EC2002. Ensure that the DB-15 thumbscrews are secured to the hex nuts on the EC2002 case.

Electrical Requirements

All wiring associated with the EC2002 installation in an aircraft should comply with FAA AC 43.13-1A Chapter 11 or equivalent requirements. All wiring should be a minimum of 22AWG in size.
Power may be supplied to the EC2002 as a switched supply from the transponder, or directly from the aircraft bus. The EC2002 can operate with a supply voltage ranging from +10V to +33V. The maximum current requirement for the EC2002 is 200mA (heater element full on, 24V Supply).

Where the power for the EC2002 is to be supplied from the aircraft bus, the positive line should be switched and passed via a circuit breaker with a rating of no greater than 1 A. Both the switch and the circuit breaker should be clearly labeled as “ALTITUDE ENCODER”. A dedicated ground line should be run from the EC2002 to the transponder, and be grounded to the transponder’s power ground to ensure correct signal levels.

EC2002Pin

Assignment

| TRANSPONDER PIN ASSIGNMENTS
---|---
Microair

T2000SFL

| King

KT76A

| Terra

TRT250

| Narco

AT- 150

| Garmin

GTX 320

| Collins

TDR- 950

1| D4| 21| | | | |
2| A1| 9| M| 5| 7| 3| 12
3| A2| 10| K| 17| 6| 5| 10
4| A4| 11| J| 16| 8| 6| 7
5| B1| 12| E| 15| 12| 9| 6
6| RS232 In| | | | | |
7| RS232 Out| 5| | | | |
8| V+| 2| A/C V+| A/C V+| 18| 14| A/C V+
9| B2| 13| C| 2| 10| 11| 5
10| B4| 17| B| 14| 9| 12| 4
11| C1| 18| D| 3| 14| 10| 8
12| C4| 20| H| 18| 13| 7| 9
13| C2| 19| L| 4| 11| 4| 11
14| V+| 2| A/C V+| A/C V+| 18| 14| A/C V+
15| GND| 3| A/C Gnd| A/C Gnd| 5| 13| A/C Gnd

Notes

1. V+ means input voltage, either switched from the transponder or direct from the aircraft bus.
2. A/C V+ means aircraft supply voltage – positive.
3. A/C Gnd means aircraft ground – negative.
4. Where the power is not supplied directly from the transponder, it is recommended that an indicator light be installed to show when power is being supplied to the encoder.

SERIAL ALTITUDE OUTPUT

The EC2002 will output a formatted ASCII message on an RS232 Data Interface. This message contains the current pressure altitude with reference to 1013 .2milli-bars or 29.92 inches of mercury. All formats use 8 data bits, 1 start bit, 1 stop bit & no parity.

Format

| Baud Rate|

Message Formatting

| Example Message (5200 feet above MSL)
---|---|---|---

Garmin AT

|

1200bps

|

AL, space, +/- sign, five altitude digits, T+25, checksum, carriage return

|

AL +05200T+25D8[CR]

Magellan

|

1200bps

|

$MGL, +/- sign, five altitude digits, T+25, checksum, carriage return

|

$MGL+05200T+250C[CR]

Northstar, Garmin

|

2400bps

|

ALT, space, five altitude digits, carriage return

|

ALT 05200[CR]

Trimble, Garmin

|

9600bps

|

ALT, space, five altitude digits, carriage return

|

ALT 05200[CR]

Microair

|

9600bps

|

STX, a=, – (if negative), five altitude digits, ETX, check sum

|   [STX]a=05200[ETX]9A

Notes:

1. The factory default setting is “software controlled” and set to GARMIN AT output with 100’ step resolution.
2. The software-controlled option allows the EC2002 to be configured from terminal software applications.
3. The Gillham output is always present and remains at 100’ step output regardless of what serial data settings are used.
4. The Microair T2000SFL (Rev 8) will self-detect any of the above protocols. Refer to the T2000SFL User Manual to select serial altitude data instead of Gillham altitude data.

TECHNICAL DRAWING

WIRING DIAGRAMS

Gillham Output

Serial Output

LIMITED WARRANTY

• The warranty period for any Microair Avionics manufactured article is dependent on the Condition of the article at time of sale and the Purchase Date.
• For New Articles the warranty period commences from the Date of Purchase and is valid for 1 year or the minimum period defined by applicable consumer law, whichever is the longer. In the absence of original Proof of Purchase, the warranty will be valid for 2 years from the Date of Factory Shipment as determined by Microair Avionics.
• For Factory Reconditioned Articles offered for sale, the warranty period commences from Date of Purchase and is valid for 12 months.
• For Factory Exchanged Articles the warranty period commences from the Date of Purchase of the original article and is valid for the remainder of the original warranty period.
• For Repaired Articles, the warranty period commences from the date of Factory Shipment and is valid for 6 months for the original defect only.
• Microair Avionics will, at its sole discretion, repair or replace any components, which fail in normal use. Such repairs or replacements will be made at no charge to the customer for parts or labor. The customer shall be responsible for any transportation costs for the return of this product to Microair Pty Ltd or an approved Microair Service Centre.
• This warranty does not cover failures due to abuse, misuse, accident, unauthorized alteration, or repairs carried out by parties other than Microair Avionics or an approved Microair Avionics Service Centre. This warranty does not cover failures where the product has not been installed or operated, in accordance with the provisions of the User and Installation manual(s).
• It shall be at Microair Avionics’ sole discretion to decide if a defect is a result of material or workmanship failure.

THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED, INCLUDING ANY LIABILITY ARISING UNDER WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, STATUARY OR OTHERWISE. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY VARY FROM STATE TO STATE, AND COUNTRY TO COUNTRY.

IN NO EVENT SHALL MICROAIR AVIONICS PTY LTD BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, WHETHER RESULTING FROM THE USE, MISUSE OR INABILITY TO USE THIS PRODUCT OR FROM DEFECTS IN THE PRODUCT.

Microair Avionics may at it discretion, refer product returns for repair or service, to a service facility closest to you. Microair Avionics reserves the right to repair or replace the product or software or offer a full refund of the purchase price at its sole discretion. To obtain warranty service, please email or call the Microair Avionics Repair line in Australia. Domestic or International Return instructions are available on our website. Please follow these instructions carefully.

• Phone: + 61 7 4155 3048
• Email: support@microair.aeo
• Website: www.microair.aero.

References

• Microair Avionics pioneering lightweight, affordable avionics
• Service / Repairs - Microair Avionics

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