The Keithley DAS-HRES is a 16-bit multifunction analog and digital I/O board for precision measurement and control in IBM PC/XT/AT and PS/2 compatible computers. It delivers high-resolution data acquisition with eight differential analog input channels, two analog output channels, and digital I/O capabilities, supported by onboard programmable timing functions.
## Technical Specifications
**Analog Input**
• 8 differential channels (HI/LO/GND)
• 16-bit resolution
• 47.6 kS/s maximum conversion rate
• Switch-selectable unipolar ranges: 0–10V, 5V, 2.5V, 1.25V
• Switch-selectable bipolar ranges: ±10V, ±5V, ±2.5V, ±1.25V
• Programmable gains: 1, 2, 4, and 8
• Absolute accuracy (autocalibration enabled): ±0.0003% FS ±1 bit (gains 1, 2, 4); ±0.0045% FS ±1 bit (gain 8)
• Absolute accuracy (autocalibration disabled): ±0.01% FS ±1 bit
• Relative accuracy: ±0.003%
**Analog Output**
• 2 channels, 16-bit resolution
• ±10V standard voltage output
**Digital I/O**
• 8-bit output port
• 8-bit input port
**Counter/Timers**
• Intel 8254 onboard 3-channel programmable interval timer
• Two channels fixed divider configuration from internal 1, 8, or 10 MHz crystal clock
• Third channel: uncommitted 16-bit binary counter
• Clock input frequency: DC to 10 MHz
• Negative active count edge
• Minimum clock pulse widths: 30 ns high / 50 ns low
**System Interface**
• Direct IBM PC/XT/AT and PS/2 model 25/30 I/O slot insertion
• DMA switch-selectable for levels 1 or 3
• Software-selectable interrupts: levels 2 through 7
• Power consumption: +5V at 1.4 A typical (1.9 A maximum)
## Key Features
• Autocalibration capability reduces absolute accuracy uncertainty to ±0.0003% FS at standard gains
• Tri-stated DMA and interrupt lines enable resource sharing with compatible peripherals
• BASIC mode call driver and external DAS driver support (VIEWDAC, EASYEST LX/AG, ASYST)
• Operating temperature: 0°C to 50°C
• Compact form factor: 13.3 in L × 4.25 in H × 0.75 in D
## Typical Applications
Precision laboratory measurement, research and development, industrial process control, and automated test systems requiring 16-bit data acquisition with multiple I/O channels in legacy computer platforms.
## Compatibility & Integration
Designed for PC-based systems with available I/O slots. DMA and interrupt resource sharing accommodates multi-peripheral configurations. Software integration via Mode Call Driver and support for industry standard MetraByte data acquisition software.
