Technical information

16
Connection of the field
protocols
Sakura V1
The V1 protocol provides 2 wire communication allowing up to 10 devices to operate on a loop. V1 connects
to terminals 9-10.
Max. distance: 6000 m
EIA-485 Modbus
The NRF590 protocol uses a shielded 3-wire EIA-485 hardware interface to communicate with the modbus
master. EIA-485 is a high speed, differential communications network that allows up to 32 devices to operate
on one network.
• Using one shielded twisted pair of 18 AWG wire, connect the EIA-485 at terminal 9 and 10.
• Termination of the EIA-485 bus at the NRF590 can be set in the operating menu (only enable on end device
in a loop)
• Connect the 3rd wire from the control system signal common (0V) to terminal 8.
• Max distance: 4000 ft (1300 m)
Whessoematic WM550
The WM550 protocol provides 2 wire, current loop communication and allows up to 16 devices per loop. For
redundancy (safety function) two wire pairs are used. They always transmit the same values. The WM550-
loops connect to terminals 9 - 10 and 14 - 15.
Max. distance: 7000 m
BPM
The BPM protocol provides 2 wire communication allowing up to 10 devices to operate on a loop. BPM
connects to terminals 9-10.
Max. distance: 10000 m
Mark/Space
For a NRF590 using the Mark/Space field communications option, the following additional wiring connections
must be made:
• Run 2 twisted pairs (one power, one communication) of 18 AWG wire (Mark/Space wires) into the upper
terminal compartment through one of the conduit entries along with the 48 Vdc power wiring.
• Connect the Mark line to terminal 10 and the Space line to terminal 9.
• Connect to power supply at terminals 8 and 11.
L&J Tankway
Including power and ground, L&J is a 4-wire system, allowing 50+ devices to be connected on the
communication bus. L&J connects to terminals 8 through 11.
GPE
The GPE protocol provides 2 wire current loop communication. GPE connects to terminal 9-10.
Grounding of the fieldbus
screen
The screen of the fieldbus cable should be connected to ground at both ends. If this is not possible due to signal
disruption by potential equalisation currents, it is advisable to connect the screen of the fieldbus cable to
terminal "00 S" at the NRF590 and to ground at the other end. The "00S" terminal provides a 500 V capacitor
between the cable screen and tank ground potential.