EL6751 – Bus node diagnostics

The CANopen fieldbus card EL6751 has a comprehensive range of diagnostic options for connected network nodes.

EL6751 – Bus node diagnostics 1:
Diagnosis of inputs in the TwinCAT tree

For each CANopen fieldbus node there is a node state input variable, which signals the status of the current slave during the runtime and can be linked, for example with the PLC.

Node State (Box-State)

EL6751 – Bus node diagnostics 2:
"Variable" tab

Node State

Meaning

Explanation

0 = 0x00

No error

Bus node is operational, communication is running correctly

1 = 0x01

Node deactivated

The node is subject to one or more of the following errors:

  • guarding/heartbeat error (failure, toggle bit error, node has changed state)
  • expected TxPDO has not been received
  • TxPDO length shorter than expected

Node has been stopped, because "Manual restart" following a node failure has been selected.

2 = 0x02

Node not found

Node not found: no answer to SDO read access to object 0x1000 at the expected node address. Check the following at the node: what node address is set, and what baud rate. Check network (terminating resistors, connectors, bus length, crossed wiring etc.)

4 = 0x04

SDO syntax error at StartUp

Error during SDO write access: SDO abort by node. See the "Diag" tab for details.
or: the length of an object read by SDO does not agree with the expected length.

5 = 0x05

SDO data mismatch at StartUp

Expected data does not agree with that read via SDO (e.g. device profile and/or additional info do not agree with object 0x1000). Can also occur if the value to be written (e.g. PDO COB-ID) is read back due to refusal of write access, and does not agree. See the "Diag" tab for details.

8 = 0x08

Node StartUp in progress

Node was found and has been started.

11 = 0x0B

EL6751Bus-OFF

CAN chip has entered the "Bus-OFF" state: transmit error counter is running

12 = 0x0C

Pre-Operational

Node has gone pre-operational (on its own account).

13 = 0x0D

Severe bus fault

General firmware error

14 = 0x0E

Guarding: toggle error

Guarding error: Toggle bit has not changed

20 = 0x14

TxPDO too short

Received TxPDO shorter than expected

22 = 0x16

Expected TxPDO is missing
  • TxPDO has not been received within the expected time interval:
  • sync interval with synchronous TxPDOs,
  • event timer with event-driven PDOs)

23 = 0x17

Node is Operational but not all TxPDOs were received

Node has been started, but at least one TxPDO has not yet been received from the node. Possible causes (e.g.):

  • The node only sends event-driven PDOs after the first event (this is not the intention of the CANopen specification, but is quite usual)
  • Too many TxPDOs have been configured
  • A TxPDO is present at the node, but no process data has been mapped
  • The TxPDO has transmission type 1...120 (synchronous), but SYNC has not yet been sent because the associated task has not been started

DiagFlag

Shows whether the box diagnostic information has changed.

Reading the Diagnostic Data via ADS

CANopen emergencies and other diagnostic data can be read out via ADS read (new data present as soon as you see the DiagFlag). The ADS Net-ID of the EL6751 must be entered for this. Other ADS parameters:

Port: 200

IndexGroup: Lo-Word = 0xF180, Hi-Word = Node-Number.

IndexOffset: See below

Length: See below

If more than 26 bytes of diagnostic data have been read out the emergency memory is reset. The DiagFlag is reset as soon as at least 108 bytes have been read starting from offset 0. Alternatively, the flag is reset after each of read access, if IndexGroup 0xF181 (instead of 0xF180) is used for the read.

The diagnostic data have the following definitions:

Offset 0,1:

Bit 1:

Boot up message not received or incorrect

Bit 2:

Emergency-Overflow

Bit 0, Bit 3-15:

reserved

Offset 2,3:

Bit 0-14:

TX-PDO (i+1) received

Bit 15:

All TX PDOs 16-n received

Offset 4,5:

Bit 0-4:

1: Incorrect TX PDO length

 

2: Synchronous TX PDO absent

 

3: Node signaling PRE-OPERATIONAL

 

4: Event timer timed out for TX PDO

 

5: No response and guarding is activated

 

6: Toggling missed several times and guarding activated

Bit 5-15:

Associated COB ID

Offset 6:

Bit 0-7:

1: Incorrect value during SDO upload

 

2: Incorrect length during SDO upload

 

3: Abort during SDO up/download

 

4: Incorrect date during a boot-up message

 

5: Timeout while waiting for a boot-up message

Offset 7:

Bit 0-7:

2: Incorrect SDO command specifier

 

3: SDO toggle bit has not changed

 

4: SDO length too great

 

5: SDO-Abort

 

6: SDO-Timeout

Offset 8,9

Bit 0-7:

SDO up/download index

Offset 10:

Bit 0-7:

SDO up/download sub-index

Offset 11:

Bit 0-7:

reserved

Offset 12:

Bit 0-7:

Abort errorClass

Offset 13:

Bit 0-7:

Abort errorCode

Offset 14,15:

Bit 0-15:

Abort additionalCode

Offset 16-19:

 

Read value (if offset 6 = 1)

Offset 20-23:

 

Expected value (if offset 6 = 1)

Offset 24-25:

 

Number of consecutive emergencies

Offset 26 - n:

 

Emergencies (8 bytes each)