Kohler CURTIS 3401T - CANopen COMMUNICATIONS - DATA OBJECTS; PDO Overview, Timing, and COB-IDs

6 — CANopen COMMUNICATIONS
pg. 47
Return to TOC Curtis Model 3401T – August 2022
MESSAGE COB-IDS
CAN messages are identified by 11-bit COB-IDs. The device does not support 29-bit COB-IDs.
EXPEDITED SDOS
e least signicant byte of an expedited SDO is known as the control byte. e following table
describes the control byte elds:
7 6 5 4 3 2 1 0
Command Specifier 0b n e s
e following list describes the control byte:
• e Command Specier eld indicates the SDO’s transfer type, which is described in the
following table:
Transfer Type Value
Write data to a device 001b
Conrm a write 011b
Request data from a device 010b
Device responds with requested data 010b
Abort SDO 100b
• Bit 4 is always 0b.
• e values of bits 0–3 depend upon whether the SDO transfers data. If the SDO does not
transfer data, these bits are always 0b. If the SDO transfers data, the bit values are as follows:
– n indicates the number of unused data bytes.
– e = 1b, which indicates the message contains data.
– s = 1b, which indicates that the n eld species the number of unused data bytes.
e following table lists the control byte values for the various transfer types:
Transfer Type Control Byte
Write data to a device Depends upon the data size:
• 1 byte = 2Fh
• 2 bytes = 2Bh
• 3 bytes = 27h
• 4 bytes = 23h
Conrm a write 60h
Request data from a device 40h
Device responds with requested data Depends upon the data size:
• 1 byte = 4Fh
• 2 bytes = 4Bh
• 3 bytes = 47h
• 4 bytes = 43h
Abort SDO 80h