Requirement to powering DPU’s / SCU's with DC Power
DPU 7900 Series; 7910, 7920, 7930 and 7940
SCU 1200 Series; 1284, 1280 and 1200
The majority of times that a user powers up a DPU / SCU is usually with 24V AC. However, DC power can also be used as an alternate.
Series 7900 DPU's:
The wiring to this can be two fold, it can be done just like the AC with pins 1 and 2 to power from the XFMR. However by doing it this way, the full 24V will be not be delivered to the unit. The recommended way to do this would be to hook either wire 1 to Power and wire 2 to ground or wire 2 to power and wire 1 to ground. This way you will get the full 24V delivered to the unit.
SCU 1200 Series:
For these units you would connect the +24V positive lead to TB1-1 and the negative lead to TB1-3 (which also must be connected to earth ground). Assuming you have sufficient 24Vdc current supplied, all the reader supply current output ratings would apply. The same local 24VDC source could be connected to more than one SCU in the same enclosure.