CASS / VDATS Interoperability Exploration

Richard D’Alessio

CDI Corporation / The M&T Company

13557 Lake Newman Street

Jacksonville, Fl. 32221

Rich.D'Alessio@cdicorp.com

Gilberto García

NAVAIR Jacksonville, FL

Code 4.8.4.4

6206 Aviation Avenue

Jacksonville, FL 32221

gilberto.garcia1@navy.mil

Jared Brown

WR-ALC/GRNBA,

Robins AFB, GA, 31098

Jared.Brown@robins.af.mil

Abstract—Reducing “the total cost of Automatic Test Systems

(ATS) to [the] Department of Defense (DoD) while defining

ways to use commercial products on the market and

preserving our legacy investments in Test Program Sets” is the

goal of the DoD ATS Executive Directorate [1]. The

Consolidated Automated Support System (CASS) / Versatile

Depot Automatic Test Station (VDATS) Interoperability

Exploration conducted over the past year (2011-2012) has

been a major step towards achieving that goal.

The DoD has already taken giant steps in reducing total cost of

ATS by creating a family standard of testers – VDATS for the

U.S. Air Force (USAF) depot level repairs and CASS family

for the U.S. Navy (USN) intermediate level repairs. With the

CASS / VDATS Interoperability Exploration, insight has been

gained into what it would take to push interoperability one

more step forward. The goal of this research is to determine

what it would take to allow VDATS Test Program Sets (TPSs)

to run on electronic Consolidated Automated Support System

(eCASS) and CASS TPSs to run on VDATS. The basic

hurdles for this task were to first figure out the requirements

for the two hardware interfaces to be compatible and then to

determine the requirements that would allow the software to

be compatible on both systems.

If the DoD created an interface between these two families of

testers, not only would a cost savings be created, but increased

capability for repairs could be achieved.

This paper will cover the results of the CASS / VDATS

Interoperability Exploration. The requirements identified

from this study cover both hardware and software differences

of the two systems.

Keywords – Interoperability, joint engineering analysis, VDATS,

CASS, TPS Transportability, Multiple Test Executives, COTS.

I. INTRODUCTION

The CASS / VDATS Interoperability Exploration was

conducted jointly with USAF WR-ALC Aerospace

Sustainment Directorate ATS Division and USN Program

Management Activity (PMA) 260 CASS Family ATS

Program Office with support from The M&T Company to

define the requirements to allow TPS transportability

between VDATS and CASS.

CASS is the Navy’s standard ATS and has been

designated by the Naval Air Systems Command for the

support of avionics / electronics systems at Navy

Intermediate Level maintenance and Fleet Readiness Center

(FRC) sites both ashore and afloat. VDATS is the USAF

standard ATS and was designed primarily for depot testing

capabilities, but is suitable for and will soon be deployed to

the Intermediate Level under controlled conditions.

The requirements for the exploration include the following:

• VDATS shall accept Interface Devices from existing

CASS TPSs

• CASS family shall accept Interface Test Adapters

(ITAs) from existing VDATS TPSs

• Shall not require manual reconfiguration of the

Interconnect Assembly (ICA) / General Purpose

Interface (GPI)

• Automatic Test Equipment (ATE) shall identify TPS

configuration i.e. CASS or VDATS

• Shall fit within existing ATE ICA / GPI real estate

• Shall maintain / improve existing TPS test integrity

A summary of some of the system differences is shown in

Figure 1.

Figure 1. Overview of System Differences

978-1-4673-0700-0/12/$31.00 ©2012 IEEE

Some of the challenges in accomplishing such a solution

include the following:

• Lack of common UUT (Unit Under Test) interfaces

o CASS Series 80 Single-Tier

o VDATS Series 90 Two-Tier

• Tester instrument incompatibilities

o Differences in instrumentation

o Parametrics, signal ranges, resolution,

accuracy

o Test Accuracy Ratio

• Unique TPS design environments

• CASS Family ATLAS (Abbreviated Test Language for

All Systems) / PAWS (Professional ATLAS

Workstation) RTS (Run Time System) and

LabWindows CVI / NI Test Stand

• VDATS LabWindows CVI ANSI (American National

Standards Institute) C Subset / USAF Test Executive

(TE)

• Ability to analyze TPSs for run time software, interface

and instrumentation requirements

• Mission objective differences between service

operational environments

Although there are significant differences between

VDATS and CASS, there are many common instruments

and parametric capabilities between the two systems. In the

results found below, requirements gaps are identified and

potential solutions are presented utilizing COTS and

custom equipment to resolve these gaps.

II. SUMMARY OF KEY RESULTS

The main efforts performed in executing this study

included the following:

• Evaluate CASS and VDATS capabilities and identify

parametric gaps

• Conceptualize hardware, software and TPS

documentation solutions to accommodate

interoperability

• Determine the range of parameters necessary to

accomplish interoperability

• Determine tangible benefits due to TPS cross service

compatibility

As the goal of the study is to determine a means of TPS

interoperability to benefit multi-services, the scope

originally included evaluating CASS TPS migration to

VDATS and VDATS TPS migration to CASS family of

testers. eCASS is in development and planned for near-

term deployment, and is expected to have significant

software commonality to VDATS. In light of this and that

initial analysis of migrating TPSs from VDATS to CASS

would prove high risk and high cost, the scope of the effort

was changed to consider migrating VDATS TPSs to eCASS

for the USAF to USN direction. It was further decided

since the design specifications of eCASS are not completely

known, that the direction of the study evolved to identifying

potential solutions for migrating only CASS TPSs to

VDATS.

Without going into great detail in analyzing TPS

migration from VDATS to eCASS, a solution in this

direction should consider the following:

• Hardware interface adapter series 80 to series 90

• Switching relays should map directly

• Test programs should be compatible

• Ancillary equipment for instrument parametric

differences

The ensuing discussion provides the results of

assessing the requirements to migrate CASS TPSs to

VDATS DA-1 series.

A detailed analysis was performed to compare CASS

Hybrid instrumentation to VDATS instrumentation, and the

details were summarized in a Requirements Traceability

Verification Matrix (RTVM) report. The report

documented all instrument parametric data including ranges

and accuracy, and identified similarities and differences

between the two testers. The results of this analysis

indicated that the two testers have much in common, yet the

differences require hardware adaptation to make compatible.

The VDATS switching relays and digital I/O meet the

CASS relay specifications, yet CASS has more relays and

more digital I/O channels than VDATS. To resolve this

gap, relay and digital I/O channel augmentation will be

needed for VDATS. Instrumentation parametric gaps must

be resolved by custom signal conditioning and / or General

Purpose Electronic Test Equipment (GPETE). An adapter

will be required to map CASS Series 80 Interface Devices

to the VDATS Series 90 ICA.

An analysis of the software differences between the

two testers with the goal of reusing existing TPS software

unveiled two probable potential solutions as shown in

Figure 2. One solution considers hosting multiple Test

Executives (TEs) on VDATS and thus running the CASS

TPS as-is, and the other considers TPS translation.

Figure 2. Methods of Using Existing TPS Software

A. Run TPS As-Is with Dual TE

The strategy around dual TE is to run CASS ATLAS

TPSs directly on VDATS with minimum or no source

modification. For this strategy to work VDATS Operating

System and Runtime software must be able to coexist with

multiple runtime systems and shall not impede or alter any

existing software or its functional use as it is proposed in

the following alternatives.

1. RTCASS TE (DirectTest)

The first TE alternative is to use Reconfigurable

Transportable Consolidated Automated Support System

(RTCASS) DirectTest Runtime. DirectTest is a proven

runtime control provider with a modular static and dynamic

layer. For this study we will focus on the dynamic layer.

Organic development will be required in DirectTest

dynamic layer, more specific in the resource and Instrument

Manager Handler (IMH) (VDATS wrappers), as shown in

Figure 3. Modifications of software wrapper functions, if

required, should be developed according to the VDATS

Wrapper Style Guide [2].

Figure 3. DirectTest Runtime TE Hosted on VDATS (Organic)

Additionally, CASS ATLAS source files will need to be

translated into a format compatible with the RTCASS

runtime [3]. RTCASS Toolbox therefore will generate the

new ATLAS files that can be consumed by the DirectTest

runtime system, as shown in Figure 4.

Figure. 4. Conversion Process With Proposed DirectTest Runtime Hosted

On VDATS

2. EADS PAWS RTS

The second TE alternative is to use Personal ATLAS

Work Station (PAWS) Run-Time System (RTS). The

PAWS software provides an instrument interface called

Control Interface Intermediate Language (CIIL) Emulation

Module (CEM) that interfaces between the PAWS RTS and

commercial instrument adapters (wrappers) as shown in

Figure 5. PAWS Developer Studio includes CEM Wizard

along with other set of tools [4] that could minimize

transportability risk, cost and future expansion.

Figure 5. PAWS RTS TE Hosted on VDATS

If RTCASS TE is selected, the TPS source files will be

translated from CASS ATLAS to RTCASS source files,

while using PAWS RTS will require minimal, if no, TPS

modification. Notice that both runtimes use ATLAS source

files as the starting point.

B. TPS Translation

Since VDATS TPS source files are in ANSI C format

and CASS is in ATLAS, TPS code translation would be

required. The translation options explored include organic

peer-to-peer, via intermediate Automatic Test Markup

Language (ATML), and other COTS solutions.

1. Organic Translation Software

a. peer-to-peer

WR-ALC organically developed an ATLAS translation

tool which converts ATLAS source to CVI. This solution

would not require hosting another runtime system on

VDATS. The usage of a peer-to-peer tool is shown in

Figure 6.

Figure 6. Peer-To-Peer Organic Translation Software

b. Via ATML

Another method is to use RTCASS Toolbox to

translate TPSs from CASS ATLAS to RTCASS, then from

RTCASS to ATML, and finally to CVI. This solution will

require organic and COTS efforts. Similar to peer-to-peer,

this solution would not require hosting another runtime

system on VDATS. The usage of an ATML tool is shown

in Figure 7.

Figure 7. ATML Organic Translation Software

2. Commercial Translation Software

Use of COTS translators could allow VDATS TPS

source code to be converted from CVI to ATLAS, Basic,

C#, C++ and ATML. Some potential COTS options are

shown in Figure 8.

Figure 8. COTS Translation Software Options

In addition to hardware and software solutions in support

of migrated TPS’s, a cohesive documentation package is

required to aid in testing migrated UUTs. The original

intent of the documentation solution portion of this study

was to determine a path to convert existing Navy CASS

TPS documentation to work with the USAF VDATS ATE.

However, as the study progressed, the Integrated Product

Team (IPT) agreed that converting multiple TPS document

packages to work on the other services’ ATE would be too

costly and time consuming. Therefore it was determined

that a potential solution could include a single USAF Test

Program Manual document that generically maps CASS

TPS documentation to typical USAF documentation. This

would include any references to typical CASS GPI, or other

assets to corresponding VDATS assets.

From the extensive analysis that was performed to

explore interoperability, a design requirements specification

was drafted. The design requirements specification

establishes the minimum performance for the stimulus and

measurement equipment, software, and interface

requirements contained in the VDATS to be compatible

with the hybrid BLK III with Synchro Generation

Measurement Asset (SGMA) configuration of the US Navy

CASS. The VDATS-DA1 stimulus and measurement,

software, and interface assets shall be used as a capability,

accuracy, and reliability baseline. Since the USAF allows

modification of VDATS testers for peculiar requirements

via a Mission Equipment Support Set (MESS), the design

requirements for CASS compatibility is proposed as a

CASS Compatible MESS. A notional CASS Compatible

MESS is shown in Figure 9.

Figure 9. CASS Compatible MESS

III. CONCLUSIONS

This paper explored hardware and software conceptual

design solutions for a CASS / VDATS interoperable TPS

sharing. There are many common instruments and

parametric capabilities between CASS and VDATS. Where

incompatibilities exist a MESS can be developed, which

would include the following:

• ICA modification to add relays and digital channels

along with GPETE

• Transportability Relay Augmentation Module and

Interface Adapter series 90 to series 80

• Utilize Multiple TEs to run CASS TPSs directly on

VDATS or translate TPSs

• TPS documentation mapping manual

From initial investigation, approximately 100 USN

TPSs are for UUTs that are also used by USAF platforms

and can be tested on VDATS. TPSs from other emerging

DoD testers could also potentially be tested on VDATS and

eCASS. This solution would be a significant step in

improving test interoperability between service ATE

platforms and achieving the following:

• Streamlining cost of DoD ATS / TPS ownership

• Reducing logistics cost and minimizing duplication of

both nonrecurring and recurring costs.

• Maintaining and improving test integrity among ATE

platforms considered for the Tri Services.

• Reducing Tri Service duplication of efforts and

operations cost.

ACKNOWLEDGEMENTS

The authors would like to thank the IPT members of

this study including the following:

• Joe Eckersley, Nathan Hinks of WR-ALC, Georgia.

• Bill Heyn, Brad Bravo, Bob Shilling of NAVAIR

Jacksonville, Florida.

• Mark Rodeghier, Hugh Smith, Brad Sherrill, Brian

Newberg of The M&T Company.

REFERENCES

[1] (2005) The DoD Executive Directorate website. [Online]. Available:

http://www.acq.osd.mil/ats.

[2] VDATS Wrapper Style Guide, Rev 000, WR-ALC, 30 Nov 2009.

[3] G. Garcia, R. Loe, B. Bravo, J. Cifredo, CASS Family TPS Support Toolset. IEEE AUTOTESTCON 2011 Proceedings, pp 396-402.

[4] (2012) EADS North America Test and Services

LabWindowsTM

, CVITM

, TestStandTM

, NI and National

InstrumentsTM

, are trademarks of National Instruments

Corporation. DirectTest and RTCASS Toolbox are

products of The Boeing Company. PAWS®

is a registered

trademark of TYX Corporation, an EADS North America

Company.