Provided by: nut-modbus_2.8.1-4ubuntu1_amd64 

NAME
socomec_jbus - Driver for Socomec JBUS UPS with RS-232 serial Modbus connection.
SYNOPSIS
socomec_jbus -h
socomec_jbus -a DEVICE_NAME [OPTIONS]
Note
This man page only documents the hardware-specific features of the socomec_jbus driver. For
information about the core driver, see nutupsdrv(8).
SUPPORTED HARDWARE
This driver supports Socomec JBUS series, online (double conversion) UPS with the following
characteristics.
1. Single phase and 3-phase UPS
2. Connection: RS-232
These are typically provided with a Netvision WEB/SNMP management card / external box that would be
better served by the snmp-ups(8) driver. In case netvision isn’t available, you can hook up the UPS
directly via the serial port and use this driver.
Currently, it has only been tested on the following model.
• DIGYS 3/3 15kVA
In theory, any Socomec JBUS model should work. It should be discovered as “Unknown Socomec JBUS” with a
numeric id that I’ll need to add it to the list of supported UPSs.
Sadly, Socomec document only mentions DELPHYS MX and DELPHYS MX elite and I have the id of my own DIGYS,
so chances are, your model will not be recognized but will probably mostly work. Please report successful
or unsuccessful results to the bug tracker or the mailing list. Make sure to include the full model
number of your UPS manually in your report.
socomec_jbus uses the libmodbus project, for Modbus implementation.
CABLING
The UPS has an RS-232 port which should be connected with a NULL-modem cable to a PC serial port. The UPS
tested has a female DB9 connector, so if you construct the cable yourself, make note of the connector
type to avoid using gender changers.
RS-232 is supported on all operating systems, either via a built-in serial port on your computer, or by
using an external USB-to-RS-232 converter. If you plan to use an USB-to-RS-232 converter, make sure it’s
supported by your operating system.
INSTALLATION
This driver should be built by default if libmodbus and development headers are available. You can force
the configure script to build it with the following arguments:
configure --with-serial=yes --with-modbus=yes
You also need to give proper (R/W) permissions on the local serial device file to allow the NUT driver
run-time user to access it. This may need additional setup for start-up scripting, udev or upower rules,
to apply the rights on every boot — especially if your device nodes are tracked by a virtual filesystem.
For example, a USB-to-serial converter can be identified as /dev/ttyACM0 or /dev/ttyUSB0 on Linux, or
/dev/ttyU0 on FreeBSD (note the capital "U"). A built-in serial port can be identified as /dev/ttyS0 on
Linux or one of /dev/cua* names on FreeBSD.
INSTANT COMMANDS
This driver does not (yet?) support sending commands to the UPS.
VARIABLES
This driver does not support writable runtime variables (see upsrw(8)): for the same reasons. Both should
be trivial to implement, but since I’ve already found one or two inconsistencies in the documentation,
I’m withholding from trying them.
KNOWN ISSUES AND BUGS
Well, it is an alpha release at best, but so far appears to report the UPS status reliably. Mostly based
on the work of Yifeng Li <tomli@tomli.me> on the huawei-ups2000 in that very same source tree.
Read failure on some JBUS addresses
The driver polls all documented JBUS addresses and it is quite possible that your UPS model does not
support one of them (e.g. the Digys does not support address 0x1020 which should provide the current UPS
status). This should be logged with LOG_ERR from modbus_read_input_registers() along with the address
that produced the error.
Data stale
Under certain circumstances, some registers can return invalid values and trigger a "data stale" error.
Once a data stale error has occurred, you should see error messages similar to the example below in the
system log.
socomec_jbus: modbus_read_input_registers(addr:XXXX, count:Z):
Illegal data address
upsd: Data for UPS [socomec] is stale - check driver
upsd: UPS [socomec] data is no longer stale
So far all known problems have been fixed by the author, but an unknown one cannot be ruled out. If you
have encountered "data stale" problems during normal uses, please file a bug report with full logs
attached.
Before troubleshooting or reporting a problem, it’s important to check your dmesg log for USB connect and
disconnect events to avoid wasting time on the NUT driver when the actual problem is USB. For example, if
someone yanks the cable out of the USB port, or if a new USB device is plugged into a USB host/hub that
is struggling to power its ports (common on single-board computers like Raspberry Pi), or if you have
flaky cabling or EMI noise, the serial converter can get disconnected from USB, at least briefly. This
creates a permanent data stale, the driver must be restarted (plugging the USB back won’t fix it, since
the driver is still using the nonexistent serial device). These USB problems usually have nothing to do
with NUT. If it’s the case, you should solve the underlying USB problem - check the cable, check the
converter, try a powered USB hub, try a full-speed USB isolator, etc.
AUTHOR
Thanos Chatziathanassiou <tchatzi@arx.net>
SEE ALSO
The core driver:
nutupsdrv(8)
Internet resources:
• The NUT (Network UPS Tools) home page: https://www.networkupstools.org/
• Socomec JBUS/Modbus Reference Guide:
https://www.socomec.com/files/live/sites/systemsite/files/GB-JBUS-MODBUS-for-Delphys-MP-and-Delphys-MX-operating-manual.pdf
• libmodbus home page: http://libmodbus.org
Network UPS Tools 2.8.1 01/16/2025 SOCOMEC_JBUS(8)