ARM Data Acquisition/Logging Module

The Astech ARM (Analogue Recording Module) is a self-contained unit which records transducer or sensor data and is small enough to install at the actual measurement location. Analogue signals connected to it are stored in memory at selectable sample rates which can range from 10,000 per second to one every 30 minutes, making the ARM suitable for dynamic or slowly changing data - or a combination of both since fast and slow channel sample rates can be mixed. A memory capacity of 262,000 measurements provide a useful recording time period, even at fast sample rates.

Choice of Sensors and Recording Modes
In order to make the ARM adaptable to a wide range of sensors/transducers, the input conditioning circuit board is in the form of a plug-in component, available in 4 or 8 channel versions according to the transducer type.

For special requirements Astech will build a custom design board to suit a particular type or combination of sensors at nominal cost.

Infra-Red Interface Simplifies Setup and Data Downloading
A high speed bi-directional infra-red link is used for communication between the ARM and laptop/PC, eliminating cabling and the need to make any physical connection. Valid operation of the link is indicated by LEDs on the infra-red transceiver interface unit and the ARM.

The infra-red communications link provides important advantages and benefits:

• Cable-free input of setup data and downloading of stored measurements - especially useful when the ARM is installed at inaccessible locations
• Up to 2 Metre isolation enables measurements from high-voltage and other hazardous areas
• Remote start/stop of recording and resetting using handheld transceiver unit
• Measurements can be transmitted through sealed glass enclosures and fluids

Start Modes and Recording Options
Setup data defining the ARM operating mode is input via an easy to use graphical user interface, available for PC in Windows 95/98/NT and XP versions. Select each input channel as Fast or Slow, select the sample rate for the fast channels, and select the relative rate for the slow channels. The software displays the maximum length log to fill the ARM memory. The Start Mode sets how the log will be started. Triggered Start Setup - the log will begin when input channels exceed the user set limits. Multiple channel triggers can be combined with a logical OR (so that any single channel can start the log) or a logical AND (so that all specified channels must trigger simultaneously to begin the log). The start mode can also be set to Delayed - to start a specified time after the start command is sent, or Rolling - where memory is filled repeatedly until the log is stopped. If the log is started from the PC and not the handheld unit, then the time delay mode can be used to start the log at a specified date and time.

Downloading and Display of Measurement Data
Once the ARM memory is full or a stop command is received, its operating mode switches to standby to maximise battery life and the memory contents are stored until overwritten by a new record operation. Subsequent downloading of data into a laptop or PC is carried out by pointing the infra-red transceiver unit at the ARM and selecting the software download command.  Downloading the 262,000 measurements from ARM memory to disc takes 55 seconds. Supplied graphical display software facilities include zoom, scale, calibrate, select traces/grid/background colours and annotation. Export facilities to various proprietary analysis packages are also provided.
 

Enclosures and Accessories to Suit the Operating Environment
An important feature of the ARM is the ability to survive and function under hostile operating conditions. Suitability for a wide range of measurement environments is ensured by providing a choice of two types of housing - a lightweight ABS enclosure or an IP67 sealable diecast enclosure. To simplify attachment of the ARM, an optional steel banding/mounting plate assembly is available. This may be used to attach the diecast enclosure version of the ARM to, for example, structural components, rotating shafts and rig frames.

Specifications: