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2. Installation
VFR Voltage Frequency Relay
2.4
Instruction Manual: VFR GBM 06/10/2021
2.5 COMMUNICATIONS
Thanks to the serial port the monitoring and control of the relay can be made by a SCADA system, a PC or PLC device.
The ports provided are:
1 two-wire
RS-485 port
→
1 twisted pair which transmits and receives alternatively is used for the data
TX and RX
Bluetooth connectivity
→
BLE 4.2 standard
(for manufacturer use only)
For the RS-485 port use shielded & twisted pair wire to minimize communication errors from noise.
A suitable type of wire is:
BELDEN#9841
,
AWG 24
which is shielded and with a characteristic impedance of
120
.
Ground the shield only at one point
[Figure 2.5]
For the RS-485 port a maximum of 35 relays can be daisy chained together in parallel mode on a communication channel for a
MAXIMUM DISTANCE OF 1000 METERS.
For larger systems, additional RS-485 channels must be added.
To increase the number of relays over 35 on single channel, consult the relay constructor.
2.6 POWER SUPPLY
Voltage ranges for the relay
→
[General Information: 1.8 SPECIFICATIONS]
Power supply connection terminals
→
[Installation: 2.4 WIRING]
The relay has no internal fuses, external protection should be applied.
Orion Italia advices the use of 1 A timed external fuse.
Figure 2.5
–
Communications