A Data Acquisition Controller (DAQ) is a device that enhances the capability & functionality of a DIC system via enabling the triggering of external devices, synchronizing the acquisition of analogue data with cameras, and exporting (in-situ) real-time DIC data. Every DIC system can be retrofitted or modernized from a master-slave camera configuration with a DAQ, if and when, testing requirements change.
Up to Eight, +/-10 V analgoue input (AI) data channels can be acquired by the DAQ from external analogue devices, such as: load cells, LVDTs, crosshead transducers, strain gauges, extensonometers, and thermocouples.
The management of analogue data is completely integrated in Istra4D meaning it can be instantly streamed, viewed & saved together with the measurement image – all in one HDF5 file.
Additionally, up to two, +/-10 V analogue output (AO) data channels are also included in the DAQ that allow real-time (in-situ), online DIC measurements to be exported from Istra4D into a materials testing machine.
In the new DAQ Gen4 series, the following new functions are included together with Istra4D V4.11
Analogue Sync In (ASI) for Peak-Valley Triggering
One Analogue Sync In (ASI) port allows an external analogue device (typically, a load cell or LVDT) to be read-into the DAQX Gen4. This allows cameras to be synchronized and triggered based on an externally generated analogue signal (such as a sinusoidal wave or rectangular pulse). A trigger can be executed exactly at the peak or valley of the analogue signal.
Analogue Inter-Step Sampling (AISS)
Analogue input (AI) values can be scanned (and saved) between successive acquisition frames/steps, giving users the possibility to filter and clean AI data signals for the improvement of measurement data quality & reliability.
Stroboscopic Pulsed Illumination via Universal Out (UO)
In Istra4D V4.11 with the DAQ Gen4 series, strobe (stroboscopic) pulse illumination triggering can be performed via the Universal Out (UO). Strobe (stroboscopic) pulse illumination triggering is considerably advantageous for tests that require fast acquisition speeds, short shutter times, and detailed spatial resolution. Users who wish to perform fatigue, vibration analysis, impact, ballistic, and high-strain rate testing could all benefit from strobe illumination.
The Trigger In (TI) is a pulsed trigger signal (IN) port into the DAQ that allows a TLL signal to start a ringbuffer or pulse mode recording. A ringbuffer recording, for one-off (burst) triggering, saves acquired measurement images directly to RAM of either a Laptop PC or Tower PC, or on onboard camera memory (i.e. for high-speed, SpeedSense cameras).
A pulse mode recording, for constant interval triggering, saves image steps to the harddisk after receiving a pulsed TTL trigger i.e. from a frequency generator.
The Sync In (SI) is a continuous synchronization signal (IN) port into the DAQ that is used for external clock triggering for the camera acquisition to be synchronized and triggered based on an externally generated signal. The SI allows a TTL sinusoidal, rectangle square, or pulsed-wave signal (typically from a frequency generator) to be read-into the DAQ as an external clock source.
The camera acquisition triggering can executed at specific phase offsets with respect to the input signal. The SI is used primarily for vibration analysis.
