Estrima Biro, Sevcon gen4, module v3

You need to get access to the CAN bus. That will be possible also without an OBD2 DIAG port. The two SEVCON units will communicate via CAN, and the dashboard display also means it's connected to the CAN bus. Connect any of the OVMS v3 CAN ports to the bus, preferrably CAN1. Depending on the bus architecture of the car, you may need to add a termination resistor between CAN H & L (120 Ohms), but that's normally not needed. You may need to try different CAN speeds, I would begin with the usual 500 kbit.

Once you've got access to the bus, you can use the OVMS CANopen toolkit to access the SEVCONs:

https://docs.openvehicles.com/en/latest/components/canopen/docs/Howto-detect-CANopen-nodes.html

The toolkit is a standard framework component and doesn't depend on a specific car to be selected.

The primary SEVCON will normally be accessable as node 1, the secondary presumably node 2 -- simply use the scan command to identify the nodes:

• copen can1 start
• copen can1 scan

(Note: I suggest you take some notes and document what you find, for others wanting to follow you)

Once you know the nodes, you can access the SEVCON registers using the readsdo & writesdo commands. Get a copy of the SEVCON Gen4 user manual and find the "Sevcon CANopen Master Object Dictionary" (spreadsheet) on the net. When using the dictionary, be aware of each register's version. You can download the DCF including register versions from the SEVCON via SDO 0x5630. I wrote a DCF download script for this long ago for OVMS V2, it should be simple to adapt that to V3: https://github.com/openvehicles/Open-Vehicle-Server/blob/master/clients/diagmode/dcf_download.pl

Accessing the SEVCON diagnostic logs and fault info is done via registers 0x4100, 0x4110, 0x4200 & 0x4300. You can also read the currently active fault codes from 0x5300. The Twizy module contains code for this, also the list of known fault codes, see: https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/blob/master/vehicle/OVMS.V3/components/vehicle_renaulttwizy/src/rt_sevcon_faults.cpp#L440

For example, to get the number of currently active faults from node 1, do: copen can1 readsdo 1 5300 1

To get an active fault code, set the index number in subindex 2, then read the code from subindex 3:

1. copen can1 writesdo 1 5300 2 1
2. copen can1 readsdo 1 5300 3

You get the idea.

As soon as the CANopen service has been started, the system will also record emergency codes from all nodes and store them as metrics. Use "metrics list co." to show them.

Some register accesses need a login to a specific login level. Write accesses may need an additional key (password), but normally only need a level 4 login. Some write accesses also need to be done in pre-operational mode. The SEVCON will tell you, and you can read in the dictionary about it. Assuming the default configuration, login to level 4 can be done as implemented here: https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/blob/master/vehicle/OVMS.V3/components/vehicle_renaulttwizy/src/rt_sevcon.cpp#L369

I'd like to read about your findings.

Note that the SEVCON doesn't need to run the standard firmware -- check the software version register to know for sure. But if it's car specific, it normally still is based on the original, and you still can use the standard register dictionary as a base.

Regards,
Michael

You need to connect GND to GND, CAN0H to "CAN High" and CAN0L to "CAN Low". You can check if one of the CAN terminal pin pairs is unused on either unit, or you can use wire-tap connectors. Make sure the connection is tight. If you're getting errors after connecting the module, try adding a 120 ohms resistor between CAN0H and CAN0L (at the module end of the cable).

Not sure though if you can (and should) configure the SEVCON to ignore errors in a master/slave setup. You should rather determine the exact cause by reading the fault registers and then try to fix the issue.

Regards,
Michael

That's why I suggested using wire-tap connectors. And yes, the Gen4 logs errors and keeps them until you clear the logs explicitly. Read my previous post on how to retrieve the logs.

No, that's not correct. See my previous post. Possibly a little bit confusing, the hardware labels are 0-2, while the software uses "can1…3".

Yes, these errors are normal on an open, unconnected CAN port, as the port will act as an antenna.

Btw… you're aware that you can simply use "can2" in the commands instead of rewiring your connector?

500 kbit is just a usual rate, but your SEVCONs may use another. Did you try 1 mbit and 250 kbit?

Please copy the text, screenshots cannot be read by search engines.

That's nice, the "copen scan" command found both units and you now know their hardware & software identities.

Register 5300.01 on node 1 does not have any active fault at the time of the command. You should check node 2 as well. It's possible the faults are not permanently active, so check out the faults log on both nodes.

See the SEVCON manual or the Twizy code on how to do this.

The faults log cnt is at 4110.02, the system log cnt at 4100.02 and the event counters at 4201+n -- see Gen4 master dictionary for details.

You can also try to get the error while the OVMS is listening on the bus. It should detect some EMCY (emergency) message and log that, as well as copy the info to the metrics.

Please copy the text, screenshots cannot be read by search engines.

That's nice, the "copen scan" command found both units and you now know their hardware & software identities.

Register 5300.01 on node 1 does not have any active fault at the time of the command. You should check node 2 as well. It's possible the faults are not permanently active, so check out the faults log on both nodes.

See the SEVCON manual or the Twizy code on how to do this.

The faults log cnt is at 4110.02, the system log cnt at 4100.02 and the event counters at 4201+n -- see Gen4 master dictionary for details.

You can also try to get the error while the OVMS is listening on the bus. It should detect some EMCY (emergency) message and log that, as well as copy the info to the metrics.