Omni8/16C/Omni8P User Manual
UMC1480R24.pdf
42
© Omniflex 2021
4.9
Connecting the Power Supply
4.9.1
With no Internal Power Supply Installed (24Vdc non Ex versions)
Without an optional internal Power Supply installed, the Omni8/16C is powered from an external 24Vdc
supply.
Connect the external 24Volt supply to terminals C-1 and C-2 on the rear of the unit. There is no galvanic
isolation provided between the 24Volt supply and the internal logic of the unit.
Table 4-3 – Power Supply Connections
Terminal
Connection
C - 1
+24 Volts +/- 15%
(20.4 – 27.6 Volts)
C - 2
0 volts
When power is correctly applied, then the Green “Pwr” indicator on the rear of the unit is lit.
Reverse Polarity Protection
The Omni16C is equipped with reverse polarity protection on these terminals. If the 24Volt supply is
connected in reverse, then a momentary short circuit will exist until the internal resettable fuse opens to
protect the unit. Once the reverse connections are removed, the unit should be left for approximately 2
minutes without power to allow time for the resettable fuse to reset.
4.9.2
With the Optional Internal Power Supply installed (non Ex versions)
With the optional internal Power Supply installed, 24Vdc is produced inside the unit from the primary
supply voltage.
24Vdc is then available as an output on Terminals C-1 and C-2.
Connect the primary supply to the supply terminals P-1, P-2 and P-3.
Table 4-4 – Power Supply Terminals
AC Option
Model C1421
85-264Vac/dc
DC Option
Model C1422
20-60Vdc
Terminal
Connection
Connection
P – 1
LIVE or +
+
P – 2
NEUTRAL or -
-
P – 3
Safety Earth
Safety Earth
