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Digital Test Instruments

Astronics T940 Series

The Astronics T940 Series of Digital Test Instruments provides up to 64 high-performance digital I/O channels in a space-saving single-wide VXI 4.0 compatible module. The T940 Series operates at data rates up to 50 MHz with 1 ns edge placement, variable slew rates, and <3 ns channel-to-channel skew.

The T940 Series of digital modules for the VXIbus provides the basis for a complete state-of-the-art digital solution at the subsystem level. The T940 Series is the solution for both legacy digital replacement and new test stations to be built for digital test including aircraft/avionics, weapons systems, spacecraft, semiconductors and medical devices.

We exploit the VXI 3.0 and 4.0 platforms to produce highly-capable and reliable digital subsystems that are backed by our proprietary digital sequencer architecture.

The T940 Series uses Field Programmable Gate Arrays (FPGA) and pin-driver technologies plus an advanced sequencer, providing a choice of fixed or variable driver/receiver personality modules to create flexible digital instrumentation.

Mix and Match Driver/Receiver Modules for Value
When configuring a digital subsystem, combine an appropriate VXI mainframe/controller, configured T940 modules that include the digital test instrument, your choice of Driver/Receiver (DR) daughter cards to meet the physical interface requirements, and software.

The T940 Series features dual sequencers that can each operate in standalone or linked modes automatically with software commands.

DR card types include a full selection of variable-voltage and fixed-voltage types, including LVDS, LVTTL, and RS-485.

Applications for a Digital Subsystem
The T940 modules form the backbone of a digital subsystem that may include switching, analog instrumentation, and even an RF subsystem.

The proven VXIbus instrumentation platform is a time-tested approach for facilitating the integration of these different technologies at the device level by allowing
the free mixing of T940 modules with other VXI modules for added functionality. In addition, the T940 modules can be pre-integrated at the subsystem level suited to a specific application.

The Racal Instruments™  1263 series and 1261B series mainframes, switching products, and other instrumentation integrate with the T940 to meet many stimulus/response needs.

If requirements are provided to us, we can propose either a subsystem or a fully integrated system to perform functional testing on a variety of complex Devices Under Test (DUTs), including satellites, weapons systems, aircraft LRUs/SRUs, and certain classes of semiconductor devices.

We are uniquely positioned to provide solutions from the device level to the turnkey system level, including all hardware and software spanning the test development tools, including the Test Program Set (TPS) itself.

Designed for High Reliability
The T940 employs comprehensive thermal design to ensure reliability with excellent cooling, monitoring, and protection.

The pin electronics devices on the DR3/9 and UR14 employ a large heat sink, but there is also an on-board temperature monitor that protects the pin electronics from overheating and provides over-temperature shutdown.

An optional Racal Instruments™ 1263HP series high-power chassis provides the additional power and cooling required for large digital test systems.

Advanced Features for Modern Digital Test Development
The T940’s innovative design is suitable for today’s challenging digital test system applications. The flexible FPGA design enables the T940 to meet special user and legacy requirements. The high-speed data sequencer provides control over test patterns, timing, and format.

Robust Protection Circuitry
All 24 V daughter-board channels can source and sink current as well as dissipate heat providing loading and high slew rates. To ensure that all channels are operating in a safe area, protection circuitry is provided for automatic fault condition detection.  The digital bias power supply is also monitored for voltage faults.

Scalable Design
Built-in scalability and modular design enable configurations from 24 to 768 single-ended channels in 24 or 32 channel increments. Each DRM can hold up to two modules of 32 single-ended channels each.


Multiple DRMs can operate both as independent 32-bit digital instruments or as a digital subsystem with up to 768 channels. 

Triggering and Synchronization
The T940 DRM features extensive control over digital testing to synchronize it with other test instruments and to control digital test sequencing.

The T940 accepts triggers from the VXI TTL Trigger Bus, VXI ECL Trigger Bus, Front Panel Auxiliary Inputs, or from any channel and provides two sync outputs per 32-channel module.

Triggers can be used (1) to synchronize the T940 with other instruments; and (2) as a test input for test sequence control. Sync outputs can be offset to the start of a test sequence or step.

Efficient Use of Power
Two power conversion options are available to best take advantage of the available VXI backplane power sources. Power converters are provided when type DR3e, DR9, or UR14 driver/receiver modules are used.

The type 1 power (code -001) converter is available for use with a traditional VXI 3.0 mainframe. For this type, backplane current is limited to what can be provided
by the standard VXI 3-row connector, and channels will shutdown if maximum power is exceeded.

The type 3 power converter (code: -003) is also available for systems using the 1263HPx VXI 4.0 mainframes. Type 3 takes advantage of VXI 4.0 power distribution, allowing the module to provide additional power, compared to type 1, without reaching its limit. 

High-Speed Data Sequencer
The high-speed data sequencer provides control over digital test patterns. Each DRM contains two data sequencers that can operate independently or synchronously for timing, memory, and control of the two front-end modules.

Sequencer logic supports full UUT hand-shaking and controls timing, format, pattern data, looping, and conditional testing. The sequencer includes definable standby and idle sequences.

Variable Voltage DR Modules
The DR3e and DR9 modules provide 32 and 24 single-ended channels in a single plug-in module. Each T940 DRM can accommodate up to two modules for up to

64 or 48 single-ended channels in a single VXI slot. The DR9 modules only include an analog port for each channel for connection to an instrument matrix, for example.

Variable voltage modules such as the DR3e and DR9 feature:

  • Six voltage ranges from -15 V to +24 V with an output swing of up to 24 V
  • Full drive current on all channels simultaneously when used with our 1263HP series mainframes
  • Programmable current load with dual commutating voltages
  • Programmable resistive input load to a programmed voltage
  • Program slew rates selectable per channel (0.2 V/ns to 1.3 V/ns, typical)
  • 12/50 Ω selectable output impedance
  • Real-time over-voltage protection on each channel
  • Robust protection circuitry for the entire  module


Fixed Voltage DR Modules
There are currently four different fixed voltage DR modules available for the T940 series:

  • DR1: Low-Voltage TTL Digital I/O
  • DR2: Low-Voltage Differential Signaling (LVDS) Digital I/O
  • DR7: RS-485 Differential Digital I/O
  • DR8: TTL Digital I/O

Digital Test Development Software

T940 Soft Front Panel
The SFP provides interactive control of the T940 digital subsystem. The easy-to-use graphical interface enables setup and configuration, calibration, and sequencer control. Channels may be setup either individually or in user-defined groups. Using the SFP, users are able to define and debug digital tests. The SFP also has the ability save digital tests for later use by the SFP or programmatically within test sets.

Digital Functional Language (DFL)
The optional DFL provides a high level programming interface to the T940, providing the capability for you to seamlessly utilize the T940 with legacy test programs. This interface enables the T940 to emulate the legacy system characteristics without changing the underlying C program that executes the digital test.

Application Resource Interface (ARI)
The optional ARI also provides an interface to legacy systems from the T940 for you to seamlessly utilize the T940 with legacy test programs. The ARI provides a higher level of control of the advanced features within the T940 compared with those in DFL which is primarily used to emulate the legacy digital subsystem.

Innovative Software Tools Speed Test Development
The VXIplug&play driver and digital resource suite application interface layer support third-party test development tools to ease development and integration into popular test environments.

The optional Microsoft® Windows® CIIL Emulation Module (WCEM) for TYX PAWS®Run Time System (RTS), one of the most popular independent implementations of the ATLAS language, provides an interface to the T940 from the IEEE standard ATLAS test language for modern test development. This interface provides support for both legacy and modern system implementations that take advantage of the higher order, signal-oriented features of IEEE ATLAS.

The optional TestCue runtime package also provides a digital test development and debug environment that is designed to be used with National Instruments TestStand. The Digital Programming support enables developers to access the T940 digital features directly within TestStand without having to use other IDE environments for programming.

Subsystem Configurations
Subsystems are configured contiguously across the VXI 3.0 or 4.0 backplane slots in a right-to-left sequence with the master module located in the right-most slot and with slave modules linking together with the master in a leftward direction.

Legacy Replacement Configurations

The T940-UR14 replaces a legacy central resources board.

The T940-DR9-DR9 replaces legacy variable-voltage I/O cards with 48 analog test channels.

The T940-DR3e-DR3e replaces 64-channel legacy variable-cards when analog test channels are not required. The T940-DR3e-DR3e can be used with or without the T940-UR14 as master because it can provide its own probe, clock, and external pause/halt I/O.


Product Features: 
  • 50 MHz digital stimulus and response with 1 ns edge placement resolution
  • Engineered for reliability with an advanced thermal design, temperature monitoring, and over-temperature shutdown
  • Innovative software tools to speed test development
  • Scalable design supports synchronized digital test systems from 24 to 768 channels
  • High-speed data sequencer provides control of stimulus/response patterns
  • Optional software tools simplify legacy replacement and preserve TPS investment