Optical Rotary Encoders
Magnetic Rotary Encoders
Hazardous Area Encoders
Non Contact Encoders
Ethernet Protocol Encoders
View All Accessories
Aerospace & Defense
Off Highway Vehicles
Oil & Gas
Measuring Conveyor Speed
Measuring Angles with Encoders
Measuring Linear Distance
Measuring with Draw Wire Encoders
Measuring Position with Encoders
Service & Support Overview
Competitor Parts List
Discontinued Encoder Guide
Product Manuals & Installation Guides
Featured Crossover Guides
Avtron Encoder Crossovers
DRC Encoder Crossovers
Sick-Stegmann Encoder Crossovers
Allen Bradley Encoder Crossovers
Accu-coder Encoder Crossovers
BEI Encoder Crossovers
Koyo Encoder Crossovers
How to Choose Feedback
Encoder Issues and Troubleshooting
White Paper Downloads
Power Point Downloads
How to Specify a Resolver
Draw Wire Encoders
Hall Effect Encoders
Encoder Accuracy vs Resolution
Encoder Wiring Best Practices
Single-Turn vs Multi-Turn Encoders
How to Split an Encoder’s Signal
Troubleshoot Encoder Signal Issues
Delayed signal rise time appears in the leading edge of each pulse as a rounded curve, while leaving the trailing edge straight. It creates the characteristic shark’s fin appearance. This can interfere with the ability of the receiving device to cleanly detect individual pulses in the stream.
Free White Paper: Understanding Encoder IP Ratings
In order for the encoder to send a signal over the wire, it effectively needs to charge the wire. The longer the cabling run, the more time this takes. Rise-time delays can also show up in encoders with open-collector output drivers. Here, the rise time depends not just on cable length but on the load, the encoder speed, and the internal pull-up resistor of the encoder. The higher the resolution, in general, the greater the delay.
Is the pulse stream asymmetric?
Do the pulses have the characteristic shark’s-fin shapes?
Is the signal cable connecting the encoder to the readout device longer than recommended for the output driver?
Are you using an open-collector output driver? If so, does it have a pull-up resistor?
Delayed signal rise times are most likely a system issue and not an issue with the encoder itself. If the distance between encoder and readout device is long, invest in a low-resistance cable. For encoders with open-collector output drivers, check the pull-up resistor. Using a pull-up resistor with lower resistance will shrink the delay and sharpen the leading edge of the poles. The trade-off is that it also increases the current to the device. This can put stress on the output driver, leading to premature failure. With open-collector output drivers, it is best to take a balanced approach. Size the resistor so that the leading edge slopes a small amount but remains within specification.