generic_modbus - Man Page

generic_modbus -h

generic_modbus -a DEVICE_NAME [OPTIONS]

This is a generic modbus driver expected to work with contact (direct) signal UPS devices, connected via modbus RIO (remote I/O) either serial or TCP/IP.

The driver has been tested against PULS UPS (model UB40.241) via MOXA ioLogikR1212 (RS485) and ioLogikE1212 (TCP/IP).

More information about this UPS can be found here:

More information about Moxa ioLogik R1212, E1212 can be found here:

The PULS UPS UB40.241 supports the following signals:

Ready contact      (DO) <--> HB
Buffering contact  (DO) <--> OL | OB
Battery-low        (DO) <--> LB
Replace Battery    (DO) <--> RB
Inhibit            (DI) <--> FSD

Digital port direction (DI/DO) assumes the device perspective

The driver’s concept is to map the UPS states (as defined in NUT) onto UPS contacts' states. The driver has an extended configuration interface implemented using variables defined in ups.conf.

The commission of modbus remote I/O server as well as UPS device is carried out following the corresponding instruction manuals. The following figure depicts the anticipated communication path and hardware interconnection:

+------+       +----------------+       +------------+       +------------+
| UPSD | <---> | GENERIC_MODBUS | <---> | MODBUS RIO | <---> | UPS DEVICE |
+------+  (1)  +----------------+  (2)  +------------+  (3)  +------------+
   |                   |
   +-------------------+
      HOST CONTROLLER

(1) Unix IPC
(2) RS232 | TCP/IP
(3) contacts

This driver supports the following optional settings in the ups.conf(5) file:

1 for X = OL, OB, LB ,HB, RB, CHRG, DISCHRG
0 for X = FSD

0:COIL, 1:INPUT_B, 2:INPUT_R, 3:HOLDING

0:NC, 1:NO

FSD_noro = 1
FSD_pulse_duration = 150

                     +-----+
                     |     |
inhibit pulse  >-----+     +------------------>
                      <--->
                      150ms


FSD_noro = 0

inhibit pulse  >-----+
                     |
                     +------------------------>

Here is an example of generic_modbus driver configuration in ups.conf file:

[generic_modbus]
  driver = generic_modbus
  port = /dev/ttyUSB0
  desc = "generic ups driver"
  # device info
  device_mfr = "PULS"
  device_model = "UB40.241"
  # serial settings
  ser_baud_rate = 9600
  ser_parity = N
  ser_data_bit = 8
  ser_stop_bit = 1
  # modbus slave id
  rio_slave_id = 5
  # UPS signal state attributes
  OB_addr = 0x0
  OB_regtype = 1
  OB_noro = 0
  LB_addr = 0x1
  LB_regtype = 1
  HB_addr = 0x2
  HB_regtype = 1
  RB_addr = 0x3
  RB_regtype = 1
  FSD_addr = 0x0
  FSD_regtype = 0
  FSD_pulse_duration = 150

This driver support the following instant commands:

load.off

executes "instant poweroff"

This driver is not built by default. You can build it by installing libmodbus and running configure --with-modbus=yes.

You also need to give proper permissions on the local serial device file (/dev/ttyUSB0 for example) to allow the run-time NUT driver user account to access it.

The generic_modbus driver intends to support generic UPS devices with contact signals through modbus TCP/RTU gateways (also known as RIO — remote I/Os). The data and signal path looks like this:

[UPSD] <--- IPC ---> [GENERIC_UPS] <--- modbus TCP/RTU ---> MODBUS-RIO <--- contacts ---> [UPS DEVICE]

On the other hand, you can setup any kind of modbus server, and configure the generic_modbus driver to connect and read or write specific registers. Your application / modbus server could then drive NUT statuses (e.g. OL, OB, HB etc) by writing over those registers.

Dimitris Economou <dimitris.s.economou@gmail.com>

nutupsdrv(8), upsd(8).