CANopen Communication Module DVPCOPM-SL 6.3 CANopen Network Status User can read the content value for H’5004>>H’01 to acquire CANopen network status message by editing ladder diagram to send SDO. When all nodes of CANopen network are all at normal work, the content value for H’5004>>H’01 is 0; when any node of CANopen network is abnormal or initializing fails, the content value for H’5004>>H’01 is 1. 6.4 Data Structure of SDO Request Message Here, SDO request message structure is for 5002/1 (index/ subindex), 5003/1 (index/ subindex), 5004/1 (index/ subindex) only and can be realized by editing information request mapping area.
Take DVPCOPM-SL, the first master module on the left of PLC as an example, below table shows the corresponding relations between message request/ response mapping area and PLC device. Data Format of SDO Request Message Command code: fixed to 01 ( Hex ) Request ID: Every SDO request message sent out should be given a request ID. CANopen master recognizes every request message via “Request ID number” which must be changed for the next communication after the communication is finished. The value range for Request ID is 00 (Hex) ~ FF (Hex). Data length: the data length of message is fixed to 4 bits. Node address: node address of CANopen network master Type:
it is fixed to 1 in SDO request message which indicates SDO data reading service. DVP-PLC Operation Manual 41 Content Value Explanation Actions FC The storage space receiving data in DVPCOPM-SL is full. Check and ensure bus cable connection is normal and then repower DVPCOPM-SL.
0 Master is in normal status -- Index Subindex Object Name Data Type Access Permission Default H’5004 H’00 Entry Unsigned 16 bits RO --- H’01 CANopen network status Unsigned 16 bits RO --- PLC Device Mapping Area Mapping Length D6000~D6031 SDO message response area 64 bytes D6250~D6281 SDO message request area 64 bytes Request Message PLC Device 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 D6250 Message header Request ID Command code D6251 Reserved Data length D6252 Type Node address D6253 Message data Main index high byte Main index low byte D6254 Reserved Subindex D6255 Data1 Data 0 D6256 Data 3 Data 2 D6257 ~ D6281 Reserved