Hello,
i'm trying to write some parameters of a frequency converter (pDrive MX Pro 4V) over the CAN-Bus.
The manual of the FC shows the following (in principle):
Writing to a parameter should look like this:
Send SDO Request (contains request code which tells the FC if i want to write or read a param, param-id's, data, ...) -> Receive SDO Response (to verify the written data)
Reading a paramter:
Send SDO Request (again the request code, param-id's, ...) -> Receive SDO Response with the data i ordered
So basically the reading and writing of a param only differ in the request code of the 1. telegram and the data.
The telegrams SDO Request & Response should look like the following:
http://www.ras-kas.net/Pics/sdo_fu.jpg (sorry, i can't insert the image directely...)
For all those operations i only have 2 VI's in the CANOpen Library: "CANopen SDO Write Object" & "CANOpen SDO Read Object". So far, so good.
My 1. question:
Reading params with "SDO Read Object" works so far, whereas i actually don't follow the given norm (Send Request -> Receive Response).
I only call the VI "CANopen SDO Read Object" with the corresponding parameters and get the data from it's output.
My question now is: Is the protocoll from the above picture CAN-Standard and does the VI adhere to it (internally sending the request und receiving the response)?
If not i don't fully understand, why i receive the correct data anyway because i don't/can't tell the VI the request code, which is required as seen in the image.
My 2. question:
When i want the write parameters of the FC i allways receive a completion code (output of the VI "CANopen SDO Write Object") with the number 134217728 ("CANopen SDO Completion Code to String.vi" tells me, that this is COE_SDO_GENERAL or "General error"). Does anyone of you have any additional information about this error?
Neither here i understand how i should send the data to the FC anyhow:
SDO Write Obejct has the following inputs:
- SDO object in, object index, object sub-index (they are all very clear and definitely correct because i can successfully read params with those)
- data:
Should i input here the pure data (Byte 4 - 7 in the above image) or should i input the whole telegram here (Request code, object index, sub-index & 4 data-bytes)?
The 2. guess would be kind of inconsequential because the seperate inputs for object index and sub-index wouldn't be necessary at all, but if i only input the 4 data-bytes here i don't know how i could/should place the necessary request code into the package...
I've allready tried both methods in many different variations but i allways get the "general error" mentioned above...
I would really appreciate if someone could help me any further or give me a little hint with the 2. question!
Also i'm really curious about the 1. question but it's not that important because at least it works correct...
Thanks
mik
