SBS IP-ENCODER-6 IndustryPack Module

The GE Fanuc / SBS / Greenspring IP-ENCODER-6 IndustryPack Module provides six channels of quadrature decoder inputs to an I/O subsystem built around any IndustryPack host board. The Encoder-6 module is ideal for determining position, velocity, and speed of rotational and linear moving objects which use bar-coding and optical detection; typical components in motion control applications.

Each channel has a dedicated quadrature decoder counter implemented using the HP HCTL-2020 integrated circuit. Each counter is 16 bits wide. When the counter overflows or underflows an interrupt is sent to one of the IndustryPack interrupt request signals. This permits the software driver to maintain an infinitely wide counter.

The input to the counter is two waveforms with a maximum frequency of 1.3 MHz. The relative position of one waveform with respect to the other determines the direction of the count. The skew between each waveform must be greater than 125 ns. Each of the two waveforms is input via a differential line receiver designed to meet the specifications of RS-422-A and RS-423-A. An index input is available for each counter, the assertion of any causing the other IndustryPack interrupt request signal to assert. The index input is normally used to initialize zero position or signal out of bounds conditions. Read only registers indicated which channels have overflowed, whether up or down, and index input assertion.