525 Programmable Motion Controller
Encoder Square Wave Signals
Sine wave signals are recommended because they are least affected by long cable lengths so that signal deterioration is negligible. TTL style encoders can also be connected to the 525 PMC. The signal levels for TTL encoders are similar to the desired amplified sine wave signals.
Figure 8 Typical Encoder Signals - Square Wave Output
Encoder Signal Quality
Any distributed capacitance in the interface cabling reacts to this frequency as an impedance to couple unwanted signals on the adjacent lead. Extreme care must be taken to minimize these unwanted effects. If care is not taken the resultant signal to the 525 PMC could look like this:
Figure 9 Encoder Signals As A Result Of Noise
The 525 PMC can not decode this properly. These signals are deteriorated because of cross coupling through the cabling. The signals have to be as shown in figure 8.
8