4A20 16 bit 100KHz A-D

The 4A20-16 is a high performance 16 bit A/D card for the PC/104 bus. The 4A20 has a true instrumentation amplifier input with 8 differential or 16 single ended inputs. The input amplifier has programmable 1X, 10X, and 100X gains. Input range can be unipolar or bipolar. Unipolar input ranges are 0V to 5V, 0V to 0.5V, and 0V to 0.05V full scale. Bipolar input ranges are -5V to 5V, -0.5V to 0.5V and -0.05V to 0.05V. A buffered reference voltage output is available for ratiometric measurements. The 4A10-16 has a maximum sampling rate of 75KHz (100KHz with reduced accuracy). The sampling rate is be determined by an on card crystal controlled timer or an external start convert input. Data transfer can be via programmed I/O, Interrupt driven, or DMA driven. A combined DMA and interrupt driven mode allows background data aquisition with minimal CPU overhead. Gain settings and channel sequence are table driven when used in the DMA mode. The 4A20 requires only +5V for operation, as all analog power is generated on cad.


4A22 18 bit  integrating A-D

The 4A22 is low power integrating 18 bit data acquisition system for the PC/104 bus. The 4A22 has 14 input channels with 500V isolation from system ground. The analog inputs have software selectable 0.5V or 5V full scale ranges. The galvanic isolation of input signals from the computer system ground eliminates ground loop problems common with high resolution A-D converters and allows floating measurements to be made. The conversion rate of the 4A22 is 16 conversions per second. The integrate time can be set to maximize either 50 or 60 Hz rejection. The 4A22 can be programmed to generate an interrupt when it has completed a conversion, allowing background data acquisition. The 4A22 can use any of the AT bus interrupts. The IRQ line selection is software programmable (no interrupt jumpers). 4A22 calibration data is stored in an on card EEPROM, so no zero or full scale adjustment potentiometers are needed. In fact, calibration requires no access to the 4A22 card itself. An on card temperature readout channel allows for software compensation of reference voltage drift if absolute maximum accuracy is required. Driver software for background data collection is supplied with the 4A22. This driver acquires data in the background on an interrupt driven basis, scales and offsets the data to user units and stores the processed data in an application program readable FIFO. Source code for the driver program and example interfacing programs is supplied with the 4A22.


4A23 20 bit  integrating A-D

  The 4A23 is a high resolution, low power,delta-sigma, A-D card for the PC/104 bus. 8 differential or 16 single ended inputs are provided.   The inputs have 500V isolation from system ground for noise elimination and to permit floating measurements.   The 4A23 has 5 programmable input ranges: 25 mV, 50 mV, 100 mV, 1V, 2.5V, and 5V full scale. All ranges except the 5V range can be bipolar.   A-D input is conditioned with a chopper stabilized instrumentation amplifier for minimum offset drift < 50 nV/oC. A high quality referenceis used to insure overall gain stability of < 10 PPM/oC Conversion rate can be programmed from 3.76 Hz to 202 Hz, with higher rates trading off conversion rate for noise.   The 4A23 can be run in polled or interrupt driven modes, allowing background data acquisition. Interrupts 2,3,4,5,7,10,11, or 12 can be used  All calibration information is stored in an on card EEPROM, so no zero or full scale calibration potentiometer are needed.   The low overall power consumption (>300 mW) reduces thermocouple induced offsets that can cause problems in lower input ranges.  An on-card temperature sensor is available for thermocouple cold-junction compensation.  Driver software for background data collection is provided, as is source code for driver and example programs.  The 4A23s reference voltage is brought out to the input connector for ratiometric type applications.


4A24 high speed 16 bit A-D

4a24 picture

 The 4A24 is a high resolution, high speed, low cost A-D card for the PC/104 bus. 200 Khz and 500 KHz models are available. On card EEPROM calibration storage and fully digital zero and span calibration eliminates potentiometers and simplifies circuitry.   A high bandwidth instrumentation amplifier is used for the input. Input channel scan sequence,averaging option, raw/calibrated data choice, and autozero option are determined by a built-in 1024 entry function table. Four function table extended multiplexor select addresses are available from the I/O connector for submultiplexing or other functions.  The averaging option in the function table allows A-D data on selected channels to be averaged from 2 to 128 times for noise reduction.  Converted data is placed in a 128K word sample FIFO so that host latency requirements are relaxed.  Conversions can be started by the timer, an external start convert input, or the host processor. Timed burst conversions (1 to 2^32-1 conversions) can be started by the host or the external start convert input.  The conversion start timer is a 24 bit, 50 MHz programmable divider for high resolution and wide conversion rate range. The 4A24 can operate in polled or interrupt driven mode. In polled mode, the data available status of the FIFO is read from a status port and if data as available, the FIFO port can be read. In the simplest polled mode, the host writes to the FIFO port to start a conversion, polls the status register for the DAV flag and then reads the A-D data from the FIFO port.   In interrupt driven mode, an interrupt is generated when the 128K word FIFO reaches a predetermined count. At this point the host can do a block I/O read from the FIFO to efficiently transfer the data to the host. The 4A24 can be programmed to use any of the available PC/104 bus interrupts.  24 general purpose I/O bits are provided. Each I/O bit can be individually programmed to be an input or output. Optional pullups are provided for all I/O bits.  All main digital logic on the 4A24 is contained in a FPGA to allow field upgradability and customization for special applications