CNC_B035

BUY: Electrical - Encoder

Require Features of All Encoders:

Must be at minimum a 25 line-count digital quadrature TTL encoder. ~ from Gecko G320 & G340

It should be at least a 200 line encoder. ~ from Gecko G320 & G340

Must be a 2-channel encoder. A 2 channel encoder has two channels that are out of phase and can be used to determine speed AND direction. A single channel encoder can only be used to determine speed. ~ from post on CNCzone

Must operate on a single +5VDC power supply. ~ from Gecko G320 & G340

50 mA maximum. ~ from Gecko G320 & G340

Notes:

It was said (on CNCzone ~ I think) that "High count encoders can limit your speed"

Encoders ~ Feedback Devices for Servo Motors:

Tachometer: This is the way Baldor defines the different encoders, however, Gecko says that no tachometer feedback is needed.

Analog:

Digital: ('optical encoder' or simply 'encoder')

Absolute:

Incremental: I believe that the encoder for Gecko must be Incremental, not Absolute.

Resolver: ~ Do not use. It will not work with ArtSoft Mach2 (& perhaps a lot more). Use Digital. "Older servos commonly used analog resolvers for feedback. These will NOT work. You need digital, optical encoders, these are very common on newer motors."

It looks like the servo motors should be PMDC (permanent magnet DC) motor. See Baldor Motors and Drives booklet Servo Control Facts (good) http://www.baldor.com/pdf/manuals/1205-394.pdf page 17. Have hard copy.

"You will need 5V optical encoders, Renco and US Digital are popular. You can buy encoders yourself from US Digital for decent prices and install them yourself. But you would be good to buy servos with proper encoders already fitted, like at homecnc. These encoders are "quadrature", meaning 4X. So 250 count per rev encoders will give 1000 pulses per rev etc... This is important as Mach2 or other step/dir software can only output so many pulses. High count encoders can limit your speed." ~ snaggletto on CNCzone

Encoder Questions and Answers:~ http://www.secomtel.com/UpFilesPDF/PDF/Agilent/Application%20Notes/motion%20FAQ.pdf. Have hard copy.

General:

For wiring diagram see; C:/Helicopter/CNC-Workstation/Controller/Gecko320Wiring.dxf I will modify and rename this drawing to match my project.

From the homecnc wiring diagram http://www.homecnc.info/servo%20box.pdf , the in/outs to the encoder are;

For information on wire see; OTHER: CNC Work Station - Controller - Wire Gage and Color

Suppliers:

HomeCNC

US Digital / optical encoders / quadrature encoders / The E2 was printed out for a sample.

Renco ~ A Renco Encoder

"I really like Renco encoders, they install with ease" ~ www.5bears.com

Agilent Incremental Encoders

Stegmann Encoders

eBay ~ Listed in category: Business & Industrial > Search Results for ' Encoder digital -(analog,resolver)'

Acquired Encoders:

All motors except for the two little Japan Servo gearmotors. However, there are shafts for encoders.

See the motors for specific information on the encoders.

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Last Revised: April 25, 2006