NAME
apc_modbus - Driver for APC Smart-UPS Modbus protocol
SYNOPSIS
apc_modbus -h
apc_modbus -a UPS_NAME [OPTIONS]
SUPPORTED HARDWARE
Generally this driver should work for all the APC Modbus UPS devices. Some devices might expose more than is currently supported, like multiple phases. A general rule of thumb is that APC devices (or firmware versions) released after 2010 are more likely to support Modbus than the USB HID standard.
Tested with the following hardware:
-
SMT1500 (Smart-UPS 1500, Firmware 9.6)
-
SMX750 (Smart-UPS X 750, Firmware 10.1)
-
SMX1500 (Smart-UPS X 1500, Firmware 15.0)
Note that you will have to enable Modbus communication. In the front panel of the UPS, go to Advanced Menu mode, under Configuration and enable Modbus.
Note
|
This driver was tested with Serial, TCP and USB interfaces for Modbus. Notably, the Serial ports are not available on all devices nowadays; the TCP support may require a purchase of an additional network management card; and the USB support currently requires a non-standard build of libmodbus (pull request against the upstream library is pending, as of at the time of this publication) as a pre-requisite to building NUT with this part of the support. For more details (including how to build the custom library and NUT with it) please see NUT PR #2063 |
Note
|
As currently published, this driver supports reading information from
the UPS. Implementation of support to write (set modifiable variables or send
commands) is expected with a later release. This can impact the host shutdown
routines in particular (no ability to actively tell the UPS to power off or
cycle in the end). As a workaround, you can try integrating apctest (from
the "apcupsd" project) with a "Test to kill power" into your late-shutdown
procedure, if needed. |
EXTRA ARGUMENTS
This driver also supports the following optional settings:
- port = string
-
Some value must be set, typically auto.
NoteThis could be a device filesystem path like /dev/usb/hiddev0
but current use of libusb API precludes knowing and matching by such identifiers. They may also be inherently unreliable (dependent on re-plugging and enumeration order). At this time the actual value is ignored, but syntactically some port configuration must still be there.
It is possible to control multiple UPS units simultaneously by running several instances of this driver, provided they can be uniquely distinguished by setting some combination of the vendor, product, vendorid, productid, serial, bus and/or device options detailed below. For devices or operating systems that do not provide sufficient information, the allow_duplicates option can be of use (limited and risky!)
- vendorid = regex
- productid = regex
- vendor = regex
- product = regex
- serial = regex
-
Select a specific UPS, in case there is more than one connected via USB. Each option specifies an extended regular expression (see regex(7) for more information on regular expressions), which must match the UPS’s entire respective vendor/product/serial string (minus any surrounding whitespace), or the whole 4-digit hexadecimal code for
vendorid
andproductid
.Try lsusb(8) or running this NUT driver with -DD command-line argument for finding out the strings to match.
Examples:
-
-x vendor="Foo.Corporation.*"
-
-x vendorid="051d*"
(APC) -
-x product=".*(Smart|Back)-?UPS.*"
-
- bus = regex
-
Select a UPS on a specific USB bus or group of buses. The argument is a regular expression that must match the bus name where the UPS is connected (e.g.
bus="002"
orbus="00[2-3]"
) as seen on Linux in/sys/bus/usb/devices
or lsusb(8); including leading zeroes. - device = regex
-
Select a UPS on a specific USB device or group of devices. The argument is a regular expression that must match the device name where the UPS is connected (e.g.
device="001"
ordevice="00[1-2]"
) as seen on Linux in/sys/bus/usb/devices
or lsusb(8); including leading zeroes.Notedevice numbers are not guaranteed by the OS to be stable across re-boots or device re-plugging. - busport = regex
-
If supported by the hardware, OS and libusb on the particular deployment, this option should allow to specify physical port numbers on an USB hub, rather than logical
device
enumeration values, and in turn — this should be less volatile across reboots or re-plugging. The value may be seen in the USB topology output oflsusb -tv
on systems with that tool, for example.Notethis option is not practically supported by some NUT builds (it should be ignored with a warning then), and not by all systems that NUT can run on. - allow_duplicates
-
If you have several UPS devices which may not be uniquely identified by the options above (e.g. only VID:PID can be discovered there), this flag allows each driver instance where it is set to take the first match if available, or proceed to try another.
Normally the driver initialization would abort at this point claiming "Resource busy" or similar error, assuming that the otherwise properly matched device is unique — and some other process already handles it.
WarningThis feature is inherently non-deterministic! The association of driver instance name to actual device may vary between runs!
If you only care to know that at least one of your no-name UPSes is online, this option can help.
If you must really know which one, it will not!
- usb_set_altinterface = bAlternateSetting
-
Force redundant call to
usb_set_altinterface()
, especially if needed for devices serving multiple USB roles where the UPS is not represented by the interface number0
(default). - usb_config_index
- usb_hid_rep_index
- usb_hid_desc_index
- usb_hid_ep_in
- usb_hid_ep_out
-
Force use of specific interface, endpoint, descriptor index etc. numbers, rather than defaulting to 0 (rarely other values in certain drivers for some devices known to use non-zero numbers). Specified as a hexadecimal number.
As a rule of thumb for
usb_hid_desc_index
discovery, you can see largerwDescriptorLength
values (roughly 600+ bytes) in reports oflsusb
or similar tools. - porttype=value
-
Set the type of the port used. Available values are serial for RS232/485 based connections, tcp for TCP/IP connections and usb for USB connections.
- port=value
-
Depending on the port type you can select a port here. For usb only auto is supported, for serial you can pass a device path like /dev/ttyS0 and for tcp you can pass a hostname with optional port like example.com:502.
- baudrate=num
-
Set the speed of the serial connection. The default baudrate is 9600.
- parity=value
-
Set the parity of the serial connection. Available values are N for none, E for even and O for odd. The default parity is N (none).
- databits=num
-
Set the data bits of the serial connection. The default databits is 8.
- stopbits=num
-
Set the stop bits of the serial connection. The default stopbits is 1.
- slaveid=num
-
Set the Modbus slave id. The default slave id is 1.
- response_timeout_ms=num
-
Set the Modbus response timeout. The default timeout is set by libmodbus. It can be good to set a higher timeout on TCP connections with high latency.
BUGS
This driver relies on advanced features of libmodbus
to talk Modbus protocol
over USB specifically (Serial and TCP are part of common library codebase).
At the time of this writing, the common library project is just expecting a
merge of the pull request with this ability.
For the time being, if your OS distribution does not ship the required feature
set, you may have to build your own libmodbus
and subsequently (re-)build NUT
against this library, as detailed in the NUT GitHub Wiki at
https://github.com/networkupstools/nut/wiki/APC-UPS-with-Modbus-protocol
The short sequence may be like follows:
cd ~/
git clone -b rtu_usb https://github.com/networkupstools/libmodbus
cd libmodbus
./autogen.sh
./configure --with-libusb --prefix=/path/to/prefix
make install
Note
|
|
cd ~/
git clone https://github.com/networkupstools/nut
cd nut
./autogen.sh
./configure --with-drivers=apc_modbus --with-usb --with-modbus \
--with-modbus-includes=-I/path/to/prefix/include/modbus \
--with-modbus-libs="-L/path/to/prefix/lib -lmodbus"
make
Note
|
|
The ./configure --enable-inplace-runtime
may be a good start to inherit
build configuration from an existing NUT deployment, as further detailed at
https://github.com/networkupstools/nut/wiki/Building-NUT-for-in%E2%80%90place-upgrades-or-non%E2%80%90disruptive-tests
AUTHORS
-
Axel Gembe <axel@gembe.net>
SEE ALSO
The core driver
Internet resources
The NUT (Network UPS Tools) home page: https://www.networkupstools.org/