FLEXIBILITY The following functions are available in many configurations giving the user the ability to specify exactly what’s needed. Interrupts are individually or globally enabled or disabled via software. A status register is provided to determine the interrupt source. ANALOG INPUTS The Analog Inputs feature software programmable gain with ranges of 0-5V, 0-10V, ±5V, and ±10V. The configuration employs an instrumentation pre-amplifier per channel which allows for differential inputs, 200V Common Mode Rejection, high input impedance, and optional factory channel by channel pre-settable gain (1-200) to accommodate low-level inputs from sensors. Inputs 4-20mA are available as a factory-installable option. ANALOG OUTPUTS Output ranges of 0-5V, 0-10V, ±5V and ±10V, are field selectable with jumpers. Note that four conversions may take place at once and that, since the D/As are double buffered, data for the next conversion may be loaded simultaneously. COUNTER TIMERS The circuit uses an 82C54 (3 sixteen bit counter/timers). The user has access to each counter/timer’s gate, clock, and output signals. The output of counter two can be used to generate an interrupt. The software package supports counting events, frequency output, pulse and frequency measurement. DIGITAL I/O The circuit uses an 82C55A PPI with mode 0 supported. Ports A and B (16 lines) are buffered and pulled up to 5V. Port C features Change of State detection.