US Digital

The PCI-3E is a PCI interface card that will track up to three incremental encoders and has an I/O port capable of handling four digital inputs and four digital outputs. Multiple cards can be used concurrently on the same PCI bus of a PC to obtain additional channels. Each encoder channel has a 24-bit real time up/down counter with a count range from 0 to 16,777,215.

The PCI-4E is available for applications where four incremental encoders and no I/O port are desired (see the PCI-4E page).

The PCI-3E provides four fast and efficient up / down counting modes for real-time data acquisition applications. These include modulo-N, non-recycle, range-limit and simple 24 bit counter mode. Quadrature input modes of x1, x2, x4 and pulse/direction can be selected. The on-board FIFO buffer stores up to 204 data records. Each record which consists of three encoder counts, a 4-bit input port reading and a 32-bit time stamp.

Time based data logging allows encoder data to be logged with precise intervals. Wide ranges of sampling periods can be programmed up to 128,849 seconds in 30 μs increments. A console application written in C (a tight loop program using no interrupts) running on a PC with a 1.8GHz processor and Windows 2000 may potentially store up to 150,000 samples per second to a data array, each sample consists of the three 24-bit encoder position counters and a 33 MHz time stamp. Due to how Microsoft Windows handles CPU time and processes, the sampling rate may periodically drop.

The output pins can be programmed to send out user defined values or send out trigger outputs of encoder channels. The input pins can be used for digital reading of user programs or programmed to detect signal edges (rising or falling) for capturing encoder counts and a time stamp.

Two versions are available: the single-ended PCI-3E-S for TTL encoder inputs or the differential PCI-3E-D for RS-422 encoder inputs.

The plug-and-play software automatically detects the existence of one or more PCI-3E cards on the PCI bus and assigns a unique device ID to each card. Demo software is included on the CD for Windows 2000/XP. The software displays the position of each encoder and allows the user to change the parameters of each channel individually. This demo software includes the source code and provides a good starting point for the development of user customizable software. LabVIEW users are also provided with the LabVIEW driver software and application.