Why I Like Copley Accelnet Servo Drives
A couple years ago I was looking for a distributed servo drive, and selected the Coley Accelnet Panel.Â There are a lot of other good servo drives out there, butÂ I like a lot of little details on the Accelnet Panel ADP drives, such as:
- The ADP uses a standard fieldbus, CANOpen, so I’m not tied to a proprietary network.
- Copley’s free CMO software makes it easy to get started with CANOpen, assuming you can use COM objects.Â Raw CANOpen has a substantial learning curve.
- The ADP uses HD (high density sub-D) connectors, so I can buy affordable, molded cables.Â The HD connector is also robust; the MDR (Micro-D Ribbon) cables on the previous model (ACJ) are a nice idea, but I can’t get affordable cables for them, and they do not have same level of mechanical robustness.
- The ADP uses RJ45 cables for CANOpen, with isolated DC/DC converters, so it’s easy to daisy chain units using affordable cables, without having to worry about providing the right voltage to the CAN line driver.
- There are no cables used for normal operation coming out the top of the bottom; this fit our mechanical footprint much better than having to deal with cables coming out three sides (front, top, bottom).Â (The serial port is on the top, but not used during operation).
- The serial port, used for setup, has fixed settings (baud rate, etc) so it’s also easy to communicate (I don’t have to start guessing at baud rate, parity, etc on an unknown servo drive).
- The CANOpen address is set via a hex (0->F) rotary switch.Â I like being able to see what a servo drive’s address is at a glance.Â DIP switches are second best; I can decode them, but it’s not as easy.Â The worst is having the address set only using a serial setup port.Â (Note: the ADP switch is actually on offset, but we always keep the offset at 0.Â You can also ignore the switch).
- The ADP buffered encoder output is great, since we need to provide the encoder output to a custom board on about half the axes.Â We don’t need to provide an encoder splitter, unlike in our older systems.
- Finally, 100% of the Accelnets I’ve bought from eBay have worked (and I’ve bought 7 ACPs so far), and that hasn’t been true for some other brands.