Vallen AMSY-6 is our fully digital multi-channel AE-measurement system. It consists of parallel measurement channels and the system front end software which runs on an external PC. A measurement channel consists of an AE-sensor, preamplifier and one channel of an ASIP-2 (dual channel acoustic signal processor). Each channel combines an analogue measurement section and a digital signal processing unit. AE-features, such as time of the first threshold crossing (arrival time), risetime, duration, peak amplitude, energy and counts, are extracted by the ASIP-2. In parallel to the feature extraction, the complete waveform can be recorded to an optional transient recorder module.

The AMSY-6 provides 4 types of measurement data:

• hit data: data that is generated when the AE-signal exceeds the threshold

• status data: data that is generated in regular time intervals

• parametric data: data of external parametric sensors which are measured at regular time intervals. Parametric data is stored with every hit and at user specified time intervals.

• waveform data: sampled AE-sensor signal.

The system front-end software runs on a PC and controls data acquisition, storage of data and is capable of analyzing data online as well as offline.

Chassis

The AMSY-6 is available in four rugged metal chassis models which accommodates up to 4, 12, 38 or 42 channels respectively. The AE system is controlled by an external PC that can easily be disconnected, e.g. for offline analysis in the hotel room. Desktop PCs, laptops, or industrial PCs can be used as well. The chassis feature:

• Connectivity: High speed USB2.0 interface for easy connection with any PC

• Investment protection: compatible with ASIP-2

• Correlation with AE: 4 (optional 8) parametric inputs for measuring, pressure, strain, displacement, etc.

• For any material: Test pulse generator is programmable up to 400V to overcome strong wave attenuation

• Audio warning: An audio unit which makes incoming AE signals audible

• Real time indicators: LEDs for displaying the most important system status information

• Fingertip fast response: Switches for manually disabling data recording

• Worldwide usage: Single range power supply 90-250 V AC, 50-60 Hz

• Ease of stack ability: Up to eight chassis can be connected into one large system with up to 254 channels

Parametric Channels

Parametric input channels can be used to monitor environmental conditions such as temperature, load, etc. and correlate it to AE-data. Four parametric input channels are available with every AMSY-6 chassis. Extension to 8 parametric input channels is possible (except for the smallest chassis).

Each input can be programmed to ±1 or ±10 V differential input voltage, added on up to ±30 V common mode voltage. Each input provides low pass filtering by a digital averaging over a user defined time interval.

Parametric data sets are generated at the user defined time interval and with every hit.

A 32 bit cycle counter for fatigue tests is also available via an analog parametric channel.

Any of the parametric input channels can be used to control the data recording. Data recording is disabled when the voltage at the selected parametric input channel is outside the user-defined limits.

AE-Signal Processors

The dual channel AE signal processor ASIP-2 is the result of more than 20 years of experience in developing digital AE systems. ASIP-2 results in a very portable AE system even at large channel counts. Different to prior versions ASIP-2 integrates two AE-channels into one board at the same form factor.

Further advantages of the ASIP-2 include:

• High resolution: 40 MHz sampling rate at 18 bit dynamic range

• High sensitivity: Lowest possible system noise due to digitally filtering the ADC data stream

• More waveform storage space: Up to 1 GB/channel, downloaded during acquisition

• Field hardened: Rugged front panel BNC-connectors for quick and easy cable connection

• Real time indicators: Front panel LEDs indicate hit-detection, preamplifier-cable-interruption, audio- and calibration-selection as well as amplitude saturation, etc.

• Advanced filter concept: Allows for narrow band triggering of wideband transient recording and noise reduction; 500 digital band-pass filters are available as well as notch filter for single frequency disturbance elimination ASIP-2 cards are plugged into one or more chassis (up to eight) which can be interconnected to form one large system.