KPCI-3140 Keithley 8-Channel, 40 MHz Counter/Timer with Digital I/O Board

The Tektronix / Keithley KPCI-3140 8-Channel, 40 MHz Counter/Timer with Digital I/O Board is an integration of sophisticated timing, frequency and event counting, and digital I/O makes it a highly versatile, cost-effective alternative to using separate counter, timer, and digital I/O cards. This board contains eight 16-bit counter/timers, four 24-bit interval timers, and 32 digital I/O lines that can be programmed for input or output. Tektronix / Keithley's extensive software suite of 32-bit DriverLINX drivers is included. DriverLINX provides both an ActiveX and DLL interface for programming languages and test panels for easy performance verification.

Each of the eight counter/timers accepts both a clock input and a gate input signal, and outputs a clock output signal. Each counter can use a time base generated from an internal clock or from an external clock. Each counter can interrupt the CPU when it reaches a count of 0. The internal clock uses a 25ns time base with output frequencies ranging from 610Hz to 40MHz. An external clock is useful for pacing counter/timer operations at rates not available with the internal clock or for pacing at uneven intervals.

The clock output signal of one counter/timer can be routed internally to the clock input signal of the next counter/timer to cascade the two counter/timers. This creates a 32-bit counter/timer. To cascade more than two counter/timers, connect the counter/timers externally using the screw terminal panel accessory.

There are two methods for controlling the gate of each counter: by software or by an external gate signal. Use the external gate signal to trigger a one-shot output or to enable event counting, frequency measurement, or rate generation when the gate signal is active.

The KPCI-3140 allows the internal clock’s output signal to be a pulsed output with either high-to-low transition or low-to-high transitions. The duty cycle (width) of the pulse can be programmed.

The KPCI-3140 provides four 24-bit internal interval timers. An example of how these interval timers can be used is to generate a periodic interrupt to the host CPU to time an event, such as reading the digital inputs or updating the digital outputs. The interval timers use an internal clock input signal requiring no external connections. The frequency of the clock output signal range from 2.38Hz to 20MHz.

The KPCI-3140 provides 32 digital I/O lines that can be programmed into 4 banks of 8 lines for input or output. The 24mA sink and 15mA source of the digital outputs can drive external solid-state relay modules.

This board generates an interrupt when any of the eight digital I/O lines corresponding to Digital I/O Port D changes state. The interrupts can be enabled one bit at a time on this port. Use this feature to monitor critical signals or to signal the host computer to transfer data to or from the board.