Measurement Computing Daq PC-Card - Manual (Page 47)

DaqBook / DaqBoard [ISA-types] / Daq PC-Card User’s Manual 10-18-00 Daq* Hardware 3-17
DaqBoard/100A, /112A, /200A, and /216A ISA Type DaqBoards
The DaqBoard/100A, /112A, /200A, and /216A are 100 kHz ISA-bus plug-in cards that provide analog-to-
digital conversion with a wide selection of signal-conditioning, signal expansion, and software support.
DaqBoards feature an on-board 512-location sequencer that lets you select any channel and gain
combination and configure each channel for unipolar or bipolar operation.
Input power for the DaqBoard comes from the host computer’s bus. Output power from the P1 connector
includes +5 VDC (pin 1) and ±15 VDC (pins 21 and 2). The section External Analog Expansion Power
(JP1) explains how to set JP1 based on power use in the system. Also, refer to the section
Power
Management in chapter 7, DBK Option Cards and Modules.
All the DaqBoards provide 16 analog inputs (expandable up to 256), 2 analog outputs, and 4 digital inputs
and outputs. Models /100A and /200A have additional digital I/O and counter/timer capabilities. The
various DaqBoard models have either 12-bit or 16-bit resolution.
•
12-bit models include model #s /100A and /112A.
•
16-bit models include model #s /200A and /216A.
Analog input capabilities are very flexible. The A/D maximum sample rate is 100 kHz (divide by number
of channels for scan rate) with a 16-channel multiplexer and a programmable-gain input amplifier. Users
can expand channel capacity to 256 analog inputs via expansion modules for multiplexing RTDs,
thermocouples, strain gages, anti-aliasing filters, and simultaneous sample and hold amplifiers. Expansion
cards and modules attach to the P1 I/O connector (refer to
Connections later in this chapter). The P1 DB37
interface is compatible with multiplexers and signal conditioners from several manufacturers.
The DaqBoard performs 100 kHz scan sequences and provides programmable delays from 10 µs to
12 hours. The unit’s 100 kHz conversion rate fixes the time skew between channels at 10 µs. The
512-location scan sequencer allows selection of the input amplifier gain for each channel. The
DaqBoard/100A and /200A can scan 16 digital inputs in the same sequence used for analog inputs (such
inputs are thus time-correlated). Optional simultaneous-sample-and-hold (SSH) cards enable DaqBoards to
sample up to 256 channels at the same instant. Scanning and timing specifications are met even with a full
complement of expansion modules. All types of transducers are scanned within the same scan group
without PC intervention.
DaqBoards offer a wide selection of triggering capabilities. The scan can be triggered by software, a TTL
signal, or an analog input level (including slope). The trigger is hardware-based to minimize trigger latency
to less than 10 µs.
Three data transfer modes are supported:
•
DMA
•
Interrupt-driven
•
Fast I/O to data memory via block move instruction REP INSW.
Real-time data can be collected at 100 K readings/s.