Discussion:
CANopen driver/device interchangeability
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dre99gsx
2008-01-10 21:40:06 UTC
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Looking for some answers:
 
I am using the CANOpen library supplied by NI trying to determine how "plug and play" my system really is.
 
1)  Currently, I am communicating with a Copley driver.  If I have a stepper motor properly controlled with my software, and decide to swtich to a different Vendor (say IMS), will I be able to plug and play with changing the software?
 
2)  Copley has an .eds file, which is their CAN library.  I believe this current driver is DS 402.  This means the onboard CAN chip is configured to accept ONLY commands related to the 402 profile, correct?
 
3)  They mentioned each vendor can have a .eds (Dictionary, or Library) calling out special PDOs.  If I am running the Copley, calling out special index's and sub-index's, and swap in a driver from a different vendor, I will not be able to have those special PDOs accomplish their tasks, correct?  In other words, I would have to go into my code and remove those specialty PDOs from Copley and replace them with any PDOs that this new vendor would have used?
 
Our purpose for CANOpen is to have a standard command set to move motors, and be able to swap out vendor drivers, without changing software.  Anything else I need to keep in mind?
A_Ryan
2008-01-11 19:10:10 UTC
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dre99gsx,
The CANOpen Library does not support .eds files. This means CANOpen Library can not parse this file and can not configure the SDO and PDOs automatically. 
If you use CANOpen standard defined SDO numbers and the standard PDOs, you could change the hardware without changing the driver, if the hardware is mapped after the same DS 402.  You are correct, if you use manufacturer defined SDOs or a custom PDO mapping, you can not interchange the hardware without changing the configuration.
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