20150413_DARPA-BAA-15-33_Attachment_5_UITS_DUT_Spec_v5a.pdf

HONEYWELL INTERNATIONAL INC.

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Universal Inertial Testing System (UITS) Device Under Test (DUT) Specification

SIGNATURE TITLE DATE

PREPARED BY Rob McCroskey Principal Scientist R&D 05/10/2012

CHECKED BY

APPROVED BY

APPROVED BY

Electronic Master in On-line Archives (word2007)

CONTRACT NUMBER: HR0011-11-C-0036

REVISIONS

LTR

B

DESCRIPTION

Comments from initial review

DATE

08/14/12

APPROVAL

LTR

V2

Update analog connector pinouts

DATE

09/19/12

V3

Fix pin 1 reference text on page 9

DATE

01/14/13

V4

Fix Table 1 for chan. 1 baud rate

04/02/13

V5

Fix Table 1 for adjustable chan. 1 baud rate

DATE

03/30/15

Restrictions applicable to use by or for the U.S.

Government: Unlimited Rights

Restrictions applicable to all other users and uses:

This copyrighted work and all information are the property of Honeywell, contain trade secrets and may not, in whole or in part, be used, duplicated, or disclosed for any purpose without prior written permission of Honeywell. All Rights

Reserved

REVISION – PAGE

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Contents 1 Introduction

1.1 Acronyms, Abbreviations, and Vocabulary

2 System Overview

2.1 System Definition

2.2 Mechanical Concept

3 Mechanical Requirements

3.1 PCB Characteristics

3.2 Analog Connection

3.3 Digital Connection

4 Electrical Requirements

4.1.1 Analog Output

4.1.2 Digital Input/Output

4.1.3 Data Format

4.1.4 Power Input

5 References

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List of Figures

Figure 1: UITS system showing the DUT and the ANGIE readout electronics

Figure 2: UITS drawing, showing the DUT (green) and ANGIE (blue)

Figure 3: DUT mounting hole pattern showing the 1” grid of #4-40 tapped holes for PCB mounting via standoffs

Figure 4: UITS view showing the four #8-32 tapped hole locations with the alignment pins

Figure 5: Allowed location of analog connector

Figure 6: UITS and DUT cable breakout and test board

Figure 7: SAMTEC shielded, differential analog cable

Figure 8: Modified PCB layout for analog connector to allow hand soldering

Figure 9: MDM-37 connector pin assignments

Figure 10: Reference schematic for driving the TI ADC1278 differential ADC

Figure 11: Block diagram for UITS digital I/O

Figure 12: Digital I/O channel mapping

Figure 13: Schematic for generation of DUT power

List of Tables

Table 1: Electrical input requirements

Table 2: Analog pinouts. The shield connections are highlighted in grey

Table 3: Digital pin assignments

Table 4 : Four-byte fixed or floating-point data format

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1 Introduction The purpose of this document is to specify the electrical, mechanical, and data format requirements for the Device Under Test (DUT) to integrate with the Universal Inertial Test System (UITS).

1.1 Acronyms, Abbreviations, and Vocabulary

AGND: Analog ground

ADC: Analog to Digital Converter

DUT: Device Under Test

GND: Ground

GPIO: General Purpose Input/Output

NC: No Connect

PCB: Printed Circuit Board

UART: Universal Asynchronous Receiver/Transmitter

UITS: Universal Inertial Test System

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2 System Overview

2.1 System Definition

The Device Under Test (DUT) is a printed circuit board containing inertial sensors to be tested by the Universal Inertial Test System (UITS). A block diagram of the UITS and DUT system is shown in Figure 1. The Agile Navigation and Guidance Integrated Electronics (ANGIE) system reads data from the DUT via analog or digital signals. The analog signals are digitized at a maximum rate of 1000 samples/sec. Digital readout is performed using eight RS-232 channels with a data format designed to transfer 32 bits at a rate of 1000 Hz (designed to exceed the ADC resolution and support single-precision floating point).

Figure 1: UITS system showing the DUT and the ANGIE readout electronics

Analog and digital data is stored locally on a USB drive and multiplexed to a readout PC on an RS-422 link. The inertial data sent by the DUT (analog or digital) will be forwarded to the readout PC for storage and real-time monitoring. Finally, programming and control of the DUT is provided with four user-defined feed-through lines.

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2.2 Mechanical Concept

A conceptual drawing of the UITS system is shown in Figure 2. The drawing shows the DUT printed circuit board (PCB) mounted directly to UITS using standoffs. The UITS base plate provides tapped #4-40 holes for standoffs on a 1” grid. This allows the DUT flexibility in total size and also provides the option of using extra standoffs in regions where extra stability is required (around a sensor region, for example, shown in the center of the PCB). The drawing shows the analog connection (left) and digital connector (right) as well. Requirements for the placement and orientation of the analog connection are given in Section 3.2.

Figure 2: UITS drawing, showing the DUT (green) and ANGIE (blue)

The DUT can also be mounted to an adaptor plate before mounting to UITS. The adaptor plate can use two 1/8” dowel pins on UITS to improve mounting alignment repeatability. In addition, four #8-32 tapped holes are included to secure the adaptor plate to UITS. Drawings for both mounting options are provided in Section 3. UITS will mount to the rate table using four ¼”-20 screws. In addition, UITS will include alignment pins for repeatable mounting to the rate table.

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3 Mechanical Requirements

3.1 PCB Characteristics

The DUT PCB has a maximum size of 5” x 8” and will mount to the UITS assembly via #4 standoffs placed on a 1” grid as shown in Figure 3. The DUT is free to use as many standoffs as needed for secure mounting. It is expected the DUT will include mounting holes at the desired locations with a ¼” diameter recommended keep out region around each mounting hole to provide clearance for the mounting screws. The expected mount-to-mount alignment repeatability is driven by the clearance around the #4 screws. With 0.015” of clearance for each screw on an 8” PCB, we would expect repeatability of about 2 milliradians.

Figure 3: DUT mounting hole pattern showing the 1” grid of #4-40 tapped holes for PCB mounting via standoffs.

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In addition to the standoff mounting assembly, four larger #8 tapped holes are included in the assembly as well as two alignment pins for securing an adaptor plate or enclosure to UITS.

These holes and pins are shown in Figure 4. This option provides increased alignment repeatability using alignment pins. With 0.002” of clearance over 6”, the expected repeatability is <350 micro radians. Note the alignment pins are 0.25” high and are not used with the PCB mounting option.

UITS will be fabricated using ¼” 6061-T6 aluminum. Care should be taken when using the alignment pins to account for thermal expansion if a different material is used for the adaptor plate.

Figure 4: UITS view showing the four #8-32 tapped hole locations with the alignment pins

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3.2 Analog Connection

The analog outputs are sent as differential pairs using a Samtec ERF8-025-05.0-L-DV-L-TR connector [1]. This is a ruggedized, latching connector that provides 16 shielded differential pairs. UITS uses 8 pairs for the analog readout and the remaining pins for power and ground.

The pinouts are detailed in Table 2 and all differential signal pins are on the same side of the connector. Due to the limited flexibility of the mating cable, this connector shall be located in the region specified in the hatched region of Figure 5 (0.5 < x < 4.5, 0.0 < y < 2.0). In addition, note the location of pin 1 in the upper right side of the connector, shown in blue. This will prevent the need to twist the cable connected to the readout board.

Figure 5: Allowed location of analog connector

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A breakout test board has been designed and fabricated that allows the analog signals from the DUT to be easily probed. By plugging the DUT cable into the analog connector input (mate to analog cable) the positive and negative signals can be probed on the 100 mil header. The schematic and layout for the breakout board can be provided to performers for DUT testing.

Note that the board provides test inputs for the UITS system as well and only J2 (analog connector input) and J4 (100 mil header) need to be populated for the breakout functionality.

Figure 6: UITS and DUT cable breakout and test board

The cable is SAMTEC part number ERDP02508.00TBRTBL3D with a cost of about $35 and a short (1-2 week) lead time. The UITS system will provide the analog cable but performers may purchase them as well for system testing with the above breakout board.

Figure 7: SAMTEC shielded, differential analog cable

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To allow easier hand soldeing of the analog connector, the pads on the PCB can be extended as shown in red in Figure 8. This allows the pad to extend past the connector body and provide access to the soldering iron and solder placement. This approach was used on the breakout board shown Figure 6.

Figure 8: Modified PCB layout for analog connector to allow hand soldering

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3.3 Digital Connection

The digital I/O contains eight RS-232 serial UART connections, four feedthrough GPIO lines, power and GND. The feedthrough lines are passed through to the UITS readout board and are available for DUT-specific tasks, such as I2C or SPI programming. The digital connector is a Cannon MDM micro-D socket with jackposts for securing the cable and connector, part number MDM-37SBSP [2]. This connector may be placed anywhere on the PCB in any orientation. Figure 9 shows the pin assignments for the connector and cable.

Figure 9: MDM-37 connector pin assignments

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4 Electrical Requirements The key electrical interface parameters are summarized in Table 1 for the analog and digital outputs.

Parameter Typical Minimum Maximum

Analog

Type Differential Pair

Number of Outputs 8

Vin 0 V 5 V

Vin+ - Vin- -2.5 V +2.5 V

Input Impedance at

ANGIE

2 KΩ

ANGIE ADC Sample Rate

1000 Hz

Digital

Type RS-232

Number of Outputs 8

UART settings Chan 1: 9600 to 921600-8-N-1 (8 data bits, no parity, 1 stop bit)

Chan 2-8: 115200-8-N-1 (8 data bits, no parity, 1 stop bit)

Message Rate 1000 Hz

Table 1: Electrical input requirements.

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4.1.1 Analog Output

Up to eight differential analog outputs from the DUT will be digitized by the UITS system using the Texas Instruments ADS1278 24-bit ADC sampled at a maximum rate of 1 kHz. The buffer circuit shown in Figure 10 will be used on the ANGIE readout board to drive the ADC from the input signals.

Figure 10: Reference schematic for driving the TI ADC1278 differential ADC

The pin assignments for the analog connector are summarized in Table 2. As noted in Section 3.2, all differential pair assignments are on one side of the connector PCB footprint. The shield connection for the differential pairs is labeled AGND/NC. This signal will be connected to AGND on ANGIE with a 10Ω resistor, providing flexibility over which end of the cable ties the shield to AGND. The preferred method is to leave the shield unconnected at the DUT, but users may tie the shield to AGND at the DUT. Finally, the 2.5V common-mode voltage used in the above circuit is provided if buffering is used on the DUT. This should be left open if not used.

The op-amp buffer and ADC schematic was based on the reference design in Texas Instruments ADS1278EVM evaluation module. [3] The module provides an easy interface to test the digitization of differential inputs using the same ADC as UITS.

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Description Pin Description Pin

AGND/NC 1 AGND/NC 2

BAT- 3 Analog Output 8 - 4

BAT- 5 Analog Output 8 + 6

AGND/NC 7 AGND/NC 8

BAT- 9 Analog Output 7 - 10

BAT- 11 Analog Output 7 + 12

AGND/NC 13 AGND/NC 14

GND 15 Analog Output 6 - 16

VCOM 17 Analog Output 6 + 18

AGND/NC 19 AGND/NC 20

NC 21 Analog Output 5 - 22

NC 23 Analog Output 5 + 24

AGND/NC 25 AGND/NC 26

NC 27 Analog Output 4 - 28

NC 29 Analog Output 4 + 30

AGND/NC 31 AGND/NC 32

NC 33 Analog Output 3 - 34

NC 35 Analog Output 3 + 36

AGND/NC 37 AGND/NC 38

BAT+ 39 Analog Output 2 - 40

BAT+ 41 Analog Output 2 + 42

AGND/NC 43 AGND/NC 44

BAT+ 45 Analog Output 1 - 46

BAT+ 47 Analog Output 1 + 48

AGND/NC 49 AGND/NC 50

Table 2: Analog pinouts. The shield connections are highlighted in grey.

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4.1.2 Digital Input/Output

Up to eight digital channels are available to readout data from the DUT. All digital data is sent via RS-232 UARTs. The settings for channels 2-8 each are 115200 baud, 8-N-1 (8 data bits, no parity, 1 stop bit). Channel 1 can be used for all digital data and has an adjustable baud rate from 9600 to 921600. The pin assignments are listed in Table 3. The feedthrough lines will pass through to ANGIE and may be used for any user-defined purpose, for example, as an RS-232 console port or I2C programming interface.

Description Pin Description Pin Rx1 1 Tx1 20

DGND 2 Tx2 21

Rx2 3 Tx3 22

Rx3 4 DGND 23

Rx4 5 Tx4 24

Rx5 6 Tx5 25

DGND 7 Tx6 26

Rx6 8 Tx7 27

Rx7 9 DGND 28

Rx8 10 Tx8 29

Feedthrough 1 11 Feedthrough 2 30

DGND 12 Feedthrough 4 31

Feedthrough 3 13 NC 32

NC 14 NC 33

NC 15 BAT- 34

BAT- 16 BAT- 35

BAT- 17 BAT+ 36

BAT+ 18 BAT+ 37

BAT+ 19

Table 3: Digital pin assignments

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A high-level block diagram for the digital circuitry on the DUT and UITS is shown in Figure 11.

Note that the ADC output is not transmitted directly on the RS-232 link but instead requires formatting via a micro processor or FPGA. The level shifter on the DUT (such as a Maxim 3232) converts from TTL to RS-232 voltage levels.

Figure 11: Block diagram for UITS digital I/O.

ANGIE

UART (x8) and Buffering on

FPGA...

DUT

Sensor ADC uP or

FPGA

Level Shifter (TTL to RS-

232)

Level Shifter (RS-232 to

TTL)

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4.1.3 Data Format

The digital data stream can be used to send values that correspond to inertial sensor output.

Two message types are allowed: a four-byte fixed-point message treated as a signed 32-bit integer or a four-byte, single precision (IEEE 704) number. These message formats are summarized in Table 4.

Byte Description Value Notes 0-1 Start Bytes 0x02 0xfe

2 Message Type 0x10 = fixed point 0x11 = floating point

3 Number words nval Number of 4-byte words in message

4-7 Word 1 Little Endian byte order

8-11 Word 2

Bytes N-5, N-2 Word nval

Bytes N-1, N Checksum XOR of message type and data bytes inclusive

Table 4 : Four-byte fixed or floating-point data format

The start and message type bytes are used with the checksum to ensure the data are aligned in the serial stream. The checksum is an exclusive-or of the message type and the data bytes inclusive (Bytes 2 to N-2 in Table 2).

The contents of the data can be inertial rates or deltas. The UITS interface will allow users to specify the type of data being sent for each channel (delta angle, e.g.) along with a scale factor and bias to allow real-time analysis of the data.

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UITS allows a maximum of eight readout channels and can mix analog and digital channels, shown in Figure 12. In addition, while eight independent digital channels are provided, channel 1 can be used to multiplex several channels via the data format in Table 4. This allows several digital channels to use a single RS-232 link. Note that multiplexing channels requires a baud rate of 921600, which is used on channel 1. The channel mapping for each run on UITS is configured using the readout PC. Note that any combination of channels may be mapped so long as the total number does not exceed eight.

Figure 12: Digital I/O channel mapping.

Analog 1 Analog 2

Analog 8

Digital 1 Digital 2

Digital 8

Digital 1.1 Digital 1.2

Digital 1.8

Chan 1 Chan 2

Chan 4 Chan 3

Chan 5 Chan 6

Chan 8 Chan 7

Available UITS Inputs

Defined Channel Map

ChanX.hx

RS-422

USB

Drive

Readout

PC

M ul tip le xe d

C ha n

D at a

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4.1.4 Power Input

The power provided to the DUT will be a feed-though of system power 12 VDC, 2A max. Figure 13 shows the schematic for the DUT power (VDUT). A power transistor allows the DUT power to be controlled from ANGIE via software and is fused and passes through a ferrite bead. Note there is no voltage regulation for the DUT power.

Power to the DUT is supplied on both the Analog and Digital connectors. It is expected the DUT will use one or the other connector for power. In cases where both connectors are used, the power pins for one connector shall be used with the other connector power pins not connected.

Figure 13: Schematic for generation of DUT power.

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5 References

1. http://www.samtec.com/documents/webfiles/pdf/erf8.pdf

2. http://www.ittcannon.com/uploadedFiles/Product_PDFs/MDM-PCB.pdf

3. http://www.ti.com/lit/ug/sbau129d/sbau129d.pdf http://www.samtec.com/documents/webfiles/pdf/erf8.pdf http://www.ittcannon.com/uploadedFiles/Product_PDFs/MDM-PCB.pdf http://www.ti.com/lit/ug/sbau129d/sbau129d.pdf

5 References