SUPPLY VOLTAGE
Supply voltage for RCS770
If USB is used, RCS770 does not need other power supply for itself. If USB is not used, an external power
supply is needed.
The external supply is connected to connector J7 or J8. If you use J8, read the section ”Jumper J14” below.
J7 is a 1.3 mm DC jack and it accepts voltage between 8 and 28 VDC. If 230 VAC socket is available,
Nokeval recommends Mascot 8311-9V-3635 AC/DC adaptor, available separately.
Supply voltage for the bus devices
It is sometimes convenient to build the RS-485 bus with a four wire cable consisting of common, power
supply, and two data lines. This is why RCS770 has four terminals on each bus connector: one of the
terminals is reserved for supply voltage. RCS770 does not generate this supply voltage and it must be
brought to connector J8 or J7. If you use J7, read the section ”Jumper J14” below.
RCS770 itself does not care which way the bus devices are powered. This power supply routing is provided
only to make the cabling easier.
The voltage can be anything as long as it does not exceed 30 VDC because there is a 33 V varistor
protecting from voltage surges.
Jumper J14
If jumper J14 is open, J7 is used to provide the supply voltage for RCS770 itself and J8 is used to provide the
supply voltage for the RS-485 bus devices.
If jumper J14 is closed, these two circuits are interconnected. You can bring the external power supply at
either J7 or J8 and in both cases the same power supply will be used for both RCS770 and the bus devices.
10
3 2
4
3
Supply
24V
3 2
4
1
2 1
1
+
-
USB
Mascot
RS-232
485 circuits
232 circuits
J14
J3
J4
J8
J7
Separate supply for
RCS770 and bus
devices
Common supply
J14
Isolation
