User manual

Static Transfer Switch

UNB

User Manual

Page 17 (28)

3.6 CAN-Bus Communication Interface

The UNB is equipped with a serial data interface according to CAN (= Controller Area Network) -specification. Two

CAN-Bus connectors are integrated in the front plate of the unit.

The UNB communicates via CAN-Bus with the connected inverters and a possibly implemented supervision moni-

toring device (UPC3 or MU1000C).

Following information is available via the CAN-Bus:

 Status information of the UNB

 Availability of the connected inverters

 Availability of the substitute mains

 Output current of the UNB

 Device temperature

 Battery-voltage at the UNB

 Frequency of source 1 and source 2

 Input- and output values of the connected inverters as follows:

o Input current

o Input voltage

o Output current

o Output voltage

o Output frequency

o Device state (okay/not okay)

(The values are measured at regular intervals via the CAN-Bus and can be called in the display).

If the signal to one of the connected inverters is interrupted, the failure message “CAN failure” is indicated and the

number of the particular inverter is shown. The numbering of the inverters automatically follows the CAN ad-

dresses in ascending order which have been adjusted at the inverters.

The output voltage of the connected inverters is controlled by the UNB via CAN-Bus according to the adjusted

value “mains voltage” in the service menu 1 (factory setting, only practicable by skilled service personnel).

When the CAN-Bus connection is inactive for more than 5 seconds the inverters automatically switch back to the

internally stored default values.

The inverters are switched off by the UNB if Ubatt> Umax (default value= 2.5V x number of cells) or Ubatt< Umin

(default value= 1.7V x number of cells) is detected by the UNB.

ATTENTION: The internally stored value (output voltage of the inverter Uo) must be the same for all of the inverters

which are connected in parallel and the same value must be adjusted at the UNB. Detailed information regarding

the adjustment of “Uo” can be found in the user manuals of the particular inverters.

The CAN bus is not relevant for the synchronization of the inverters. For safety reasons, the synchronization takes

place via the hard-wired synchronization bus between inverters and UNB (please see section 3.3.3 ff “connectors”).