MREL DATA TRAP II, Operation Manual

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7.4 Details of Items Required but Not Supplied
7.4.1 Strain Gauges
The required strain gauges will need to match the delivered Pre-Amplifier resistance. This is 120 ohm (standard) or 350 ohm (requested
specially).
7.4.2 External Trigger
The user can not trigger internally from a strain channel. If only strain measurements are being made, an external trigger is required. This
can be as simple as a push button with the settings of the
DataTrap II™ Data/VOD Recorder set to make. Refer to the external trigger
section of this manual for more details on the different trigger methods. The external trigger is not required IF the user is recording another
channel that can be used (either scope or the optional
VOD ).
7.5 Installation Of Software
Refer to the
DAS™ Data Acquisition Suite Manual.
7.6 Preparing The DataTrap II™ For A Strain Gauge Test
A Strain Gauge test can be set up with a pre-programmed set of values or more specific settings, including VOD channels, can be set up
using the normal settings software, then the values for the channels using the Strain Gauge can be entered later.
A Strain Gauge test must be set up with the following settings:
1. The Voltage Range must include [0 to 7.5] Volts. A wider range, such as +/- 7.5 or +/- 10 Volts can be used to allow later flexibility
of use of channels in the field if other devices might be used on some channels. If some channels are set as VOD , make note of
them. The setting of each channel can be checked in the field using the LED menu on the DataTrap II™ Data/VOD Recorder before
attaching cables.
2. If none of the channels are VOD , Trigger Type should be set to External for the channels that will have Strain Gauges attached. VOD
channels can be set to internal trigger with the Strain Gauge channels set with no trigger – they will trigger when the VOD channel
triggers.
3. During the test, record which channels used a Strain Gauge and the Gauge Factor Values for these channels.
4. During the downloading of the test the gauge factors for each channel can be entered.
7.7 Field Setup Of The DataTrap II™ Strain Gauge System
The steps to collect Strain Gauge data with the DataTrap II™ Data/VOD Recorder are detailed below:
1. Turn on the DataTrap II™ Data/VOD Recorder and confirm that there are tests remaining on it and the battery has been charged.
2. Connect one end of the 3-pin Signal Condition Power Cable to the DC Out port on the back of the DataTrap II™ Data/VOD Recorder
and the other end of the 3-pin cable to the Signal Conditioner Lid . If the power light does not come on, check that the cable has been
connected correctly.
3. Connect the External Trigger cable. The power and data cables for each channel must now be set up as detailed below.