Is the isolated RS485 to USB (Hjelmslund) adapter a strict requirement, as per USB bus device recognition perhaps ?
Case in point: I have a genset with a DSE5220 controller and the official DSE P810 USB adapter that is, as far as I can identify, an isolated RS485 adapter.
So I’d rather simply use that one.
If need be I do have a Hjelmslund adapter but I’m not sure if the RS485 port on my DSE controller is functioning properly, as there were no pins on the PCB contact pads.
Memo to myself: bring the genset online again and see what works.
Since the solar panels are up on my construction yard the genset hasn’t run and was disconnected.
The recommendation to use an isolated RS485 to USB interface from Hjelmslund is based on the fact that we currently have no information as to whether and, if so, in which devices DSE installs galvanically isolated RS485 ports.
The problem with non-insulated connections is that ground loops can occur due to different earthing potentials, which can potentially damage both the DSE controller and the GX device. DSE illustrates this in this document (requires an account) with reference to a USB connection between the controller and a laptop. The requirement to use the isolated Hjelmslund interface is therefore relevant for device safety; with regard to data transmission, a Victron RS485 to USB interface would also work.
If I remember correctly, we already tested your DSE P810 USB and had communication issues with it. This can be due to many things, an incompatible usb-to-serial chip, cabling problems, a hardware defect, etc. As we do not currently see a high demand for this device, we have decided to not investigate it further and invest our R&D resources elsewhere, I’m sorry.
As usual, things are busy but otherwise rather OK here.
I remember you got things ‘more or less’ working between my DSE and my test GX using the P810 interface, but indeed with communication issues.
I did buy and install the Hjelmslund isolated interface by soldering pins on the RS485 pads on my DSE controller but was unable to verify if that actually functioned, due to lack of time and the genset being disconnected and stowed away again.
What I did notice was that the ethernet cable I used was damaged, so that might account for the communication problems.
Now that RS485 support is included in v3.50, I’m triggered to re-try my tests.
“When I have some time” I’ll see to hook up the genset again (with fresh cables) and see what I can get working.
Mainly I need to connect the battery to a charger or the DSE will drain it.
Do you have some test commands I can run on the GX CLI or a Linux machine to test RS485 communication with the DSE ?
our software expects a Modbus RTU connection with either 19200 or 115200 baud with the DSE answering on either unit id 1 or 10. You can check the logs with tail -F /var/log/dbus-modbus-client.ttyUSB0/current | tai64nlocal. You might have to adjust the device to ttyUSB1 or ttyUSB2 etc., that depends on your system.