FC 300 CANopen
32 MG.33.J1.02 VER. 050301 – VLT is a registered Danfoss trademark
Process Data Objects (PDO)
There are four read (receive) PDOs and four write (transmit) PDOs for the frequency converter.
Real-time process data is communicated using the PDOs.
The format of the structure is as follows:
PDO Communication Parameter Record
Index Sub-Index Field In PDO Communication Record Data Type
0020H 0H Number of supported entries in the record Unsigned8
1H COB-ID used by PDO Unsigned32
2H Transmission type Unsigned8
3H Inhibit time Unsigned16
4H CMS priority group Unsigned8
If the device supports the identifier distribution via DBT the value on sub-index 0H is 4, otherwise it is
2 (inhibit time not supported) or 3. The COB-ID at Index 20H, Sub-Index 1H is defined using data
type Unsigned32 in order to cater for 11-bit CAN Identifiers as well as for 29-bit CAN identifiers. The
entry has to be interpreted as defined in the following figure and table
Structure of PDO COB-ID entry
Unsigned32
MSB LSB
bits
31 30 29 28-11 10-0
11-bit-ID 0/1 0/1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0
11-bit Identifier
29-bit-ID 0/1 0/1 1 29-bit Identifier
Description of PDO COB-ID entry
Bit number Value Meaning
0 PDO valid
31(MSB)
1 PDO not valid
0 RTR allowed on this PDO
30
1 No RTR allowed on this PDO
0 11-bit ID (CAN 2.0A)
29
1 29-bit ID (CAN 2.0B)
0 If bit 29=0
28-11
X If bit 29=1: bits 28-11 of 29-bit-COB-ID
10-0 (LSB)
X Bits 10-0 of COB-ID
The PDO valid/not valid permits selection of PDOs to be used in the operational stage.
PDOs may be fully configured (e.g. by default) but not used, and therefore set to "not valid". Bits 29
and 30 may be static (not changeable), e.g. due to hardware restrictions, in which case no error is
signalled on the attempt to change them.
PDO Usage
The real-time data transfer is performed by means of "Process Data Objects (PDO)". PDOs are
represented by CMS objects of type "Stored-Event". Hence the transfer of PDOs is performed with no
protocol overhead.
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