Measurement Computing LogBook Series - Manual (Page 46)

4-2 System Expansion 957096 LogBook User’s Manual
LBK2 , 4-channel Digital-to-Analog Output card . The LBK2 Digital-to-Analog output board contains
four 16-bit, voltage-output, digital-to-analog converters with a maximum update rate of 100 kHz per
channel. The board is intended for waveform generation, UUT (Unit Under Test) stimulus, and signal
feedback. Each converter has a fixed, full-scale output of ±10 VDC. The board’s operation must be
programmed through LogView.
What are DBK Options?
DBK option cards and modules exist for signal-conditioning, analog output, system I/O, auxiliary power,
and expansion. Various sensor types are accommodated, including high-voltage/current, strain gages,
thermocouples, isolation, relays, accelerometers, filtering, and simultaneous sample and hold.
Reference Notes:
• For a general introduction to DBKs, refer to the DBK Basics section of this
manual. The text discusses the various categories of DBKs, connectivity issues,
tips on setting up a data acquisition system, and power considerations.
• DBK options are detailed in DBK Option Cards & Modules User’s Manual
(p/n 457-0905). As a part of product support, the manual is automatically loaded
onto your hard drive during software installation. The default location is the
Programs group, which can be accessed throught the Windows desktop.
No matter what the signal input from the transducer, DBKs produce output signals suitable for analog-to-
digital conversion (ADC). The output signals can be bipolar (typically -5 to +5 V) or unipolar (typically
0 to 10 V). The user can select a range of relevant values to correspond to the lowest and highest signal—
this range selection guarantees the highest resolution in 16-bit conversion by the ADC.
Note: DBKs vary in their outputs and gain settings. Refer to the specifications for the particular DBK
used.
Basic Connection Concepts
Most system expansions stem from the 37-pin Signal I/O ports P1, P2, and P3. Note that LogBook/360
combines the features and capabilities of LogBook/300 with those of a DBK60 expansion chassis. In
addition, LogBook/360 has a pre-installed serial communications card that provides GPS and AUX serial
ports as detailed in the chapter entitled, LBK and other non-DBK Options.
• P1. Each of 16 main (base) channels can support up to 16 sub-channels and thereby provide
expansion up to 256 analog input channels. LogBook’s channel sequencer scans expansion channels
at the same high speed as the base channels. DBKs can be daisy-chained off the P1 connector of
LogBook or an expansion module. Some DBKs add another level of multiplexing and
programmable gain to each channel, and setting channel parameters properly sometimes requires
both hardware and software setup.
• P2. The Digital I/O port can accommodate the DBK20/21 (digital I/O cards), DBK23/24 (isolated
digital input/output chassis), DBK25 (8-channel relay card), and other compatible devices; up to
208 digital I/O lines.
• P3. The Pulse Frequency port can be used for analog output and other uses. A DBK11A provides
for easy signal connection via screw terminals or optional BNC connectors.
The following figure illustrates various expansion possibilities. Note that additional options exist.
DBK options are detailed in the DBK Option Cards and Modules User’s Manual (p/n 457-0905).