With SSI there is only a clock and data. The begining of a frame is determined by the amount of pause time between two clock streams. In Roboteq controllers, the SSI transfers use a kHz clock, so a full bit data frame is captured in 60us. Transfers are synchronized with the 16kHz PWM frequency. The controller intelligently compensates for the fact that the angle data is read a full 60us after it was captured by the sensor, and therefore is no longer a perfectly accurate measurement of the position at the time it is read.
The controller also estimated the rotor position during the PWM cycle where it is the sensor is no read. The result is a rotor angle capture that is very timely, accurate and of very high resolution. Index of All Products. Signal Enhancement Repeater Converter Splitter. Accu-Coder Bore Inserts. Flexible Shaft Couplings. Linear Cable Adaptors. Protective Encoder Covers. Programmable Encoder Accessories. SSI encoders use two twisted pair wires plus two wires for power.
The data rate of SSI protocol encoders depends on both resolution and cable length. Clock frequencies can be as high as 1. However, as clock frequency increases, the maximum cable run decreases, a limitation common to all protocols. This problem can be mitigated by utilizing shielded cables with twisted pairs but this will increase cabling costs. Learn more about encoder wiring here.
Rotary Encoders. Noise Protection. Noise protection is extremely important for proper encoder operation, especially when data is being sent serially. Customer :. Multi-turn Data Format: The preset wire defines the current actual shaft position as zero position if it is set to the supply voltage level for more than two seconds.
Single Turn Data Format: The direction wire defines the positive direction of counting when the shaft rotates. Maximum Data Transmission Rate The data transmission rate is dictated by the master clock frequency.
Noise Protection Noise protection is extremely important for proper encoder operation, especially when data is being sent serially. When doing so, do NOT connect the end near the encoder.
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