GENERIC_MODBUS(8)

NAME
generic_modbus - Driver for contact (direct) signal UPS devices connected via modbus remote I/O gateways

SYNOPSIS

generic_modbus -h

generic_modbus -a DEVICE_NAME [OPTIONS]

    Note

    This man page only documents the specific features of the generic_modbus driver. For information about the core driver, see nutupsdrv(8).

SUPPORTED HARDWARE

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:
    https://products.pulspower.com/ca/ubc10-241-n1.html

More information about Moxa ioLogik R1212, E1212 can be found here:
    https://www.moxa.com/en/products/industrial-edge-connectivity/controllers-and-ios

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.

HARDWARE INTERCONNECTION

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

EXTRA ARGUMENTS

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

  Generic:

device_mfr=value
    A string specifying the manufacturer of the UPS device (default UNKNOWN).

device_model=value
    A string specifying the model of the UPS device (default UNKNOWN).

  Serial:

ser_baud_rate=value
    A integer specifying the serial port baud rate (default 9600).

ser_data_bit=value
    A integer specifying the serial port data bit (default 8).

ser_parity=value
    A character specifying the serial port parity (default N).

ser_stop_bit=value
    An integer specifying the serial port stop bit (default 1).

  Modbus:

rio_slave_id=value
    An integer specifying the RIO modbus slave ID (default 1).

  States (X = OL, OB, LB, HB, RB, CHRG, DISCHRG, FSD)

<X>_addr=value
    A number specifying the modbus address for the X state.

<X>_regtype=value
    A number specifying the modbus register type for the X state

Default values:

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

Valid values:

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

<X>_noro=value
    A number specifying the contact configuration for the X state (default 1).

Valid values:

        0:NC, 1:NO

        Note
        NO stands for normally open and NC for normally closed contact

  Shutdown

FSD_pulse_duration=value
    A number specifying the duration in ms for the inhibit pulse. If it’s not defined, signal has only one transition depending on FSD_noro configuration.

    Examples for FSD signal configuration:

    FSD_noro = 1
    FSD_pulse_duration = 150

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

    FSD_noro = 0

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

CONFIGURATION

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

INSTANT COMMANDS

This driver support the following instant commands:

load.off
    executes "instant poweroff"

INSTALLATION

This driver may be 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.

OTHER NOTES

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.

KNOWN ISSUES

  Using host names for UPS NMC

An UPS network management card may be assigned a fixed/static IP address or a dynamic one (e.g. by DHCP) in your network. Due to this, you may want or have to use a dynamic naming service to access the UPS. Note that this may become a problem specifically during large outages and shutdowns, when your DHCP/DNS server might already go down while the driver needs to resolve the name involved (especially during late-shutdown hooks, when a new instance of the driver program might start just to tell the UPS to power off or to power-cycle).

It may be wise to ensure your OS name service client can cache the UPS name sufficiently long, or to use fixed IP addressing (and an entry in /etc/hosts for good measure, so you only have one spot to eventually re-configure this).

AUTHOR

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

SEE ALSO

  The core driver:

nutupsdrv(8), ups.conf(5)

  Internet resources:

    • The NUT (Network UPS Tools) home page: https://www.networkupstools.org/historic/v2.8.4/

    • libmodbus home page: http://libmodbus.org