Rice Lake iQUBE2 Digital Diagnostic Junction Box - Manual (Page 62)

58 iQUBE 2 Installation Manual
8.3 Power Considerations
The iQUBE 2 can be powered either by the internal power supply (PN 76556) or by an external DC power supply.
iQUBE 2 CPU boards accept input voltages in the range 6–12 VDC.
AC Powered Option (PN 76556)
The iQUBE 2 circuit boards are optimized to receive power from the internal 7.5 VDC power supply (PN 76556).
This option provides 25 watts of power, with continuous current of 3.33 amps, and can power a complete 16-chan-
nel system under typical conditions. The internal power supply requires AC power to be available at the scale, but
offers the greatest protection from inductive transients.
DC Powered Option (PN 108434)
The approved remote 12 VDC power supply for the iQUBE 2 (PN 108434) provides 44.4 watts of power, with con-
tinuous current of 3.7 amps, to power a full system over typical distances from scalehouse to scale. The remote
power supply is mounted in an 8 x 6 x 4-inch NEMA 4X FRP enclosure and includes a transient protection board,
PN 110949.
The transient boards will handle the maximum current provided by the power supply, but large current loads
increase the voltage drop across the inductive chokes and could reduce the input voltage to the iQUBE
2 system
below the 6 VDC minimum. See Section 8.3.2
8.3.1 System Current Draw
Tables 8-1 and 8-2 show the current requirements for the iQUBE 2 CPU board and communications options cards.
System current draw is the sum of the individual current requirements.
Current Draw Example:
The current requirements for a truck scale system using 10 x 700
 load cells and a fiber-optic communications
card would be calculated as follows:
• 3 x CPU boards @ 360 mA each = 1080 mA
• 10 x 700
 load cells @ 17 mA each = 170 mA
• 1 x fiber-optic card @ 25 mA = 25 mA
The sum of these current requirements gives:
1080 mA + 170 mA + 25 mA = 1275 mA
CPU Board Loads Current Draw
Nominal CPU board load 360 mA
Per 700

load cell 17 mA
Per 350

load cell 24 mA
Per summed platform (4 x 350

load cells) 60 mA
Per I/O channel (maximum) 25 mA
Table 8-1. CPU Board Current Draw
Option
Card PN Option Description
Current
Draw
77143 Fiber-optic card 25 mA
77142 Ethernet card 195 mA
108671 Wireless LAN card 320 mA
93245 USB card 27 mA
108579 Serial expansion card 100 mA
Table 8-2. Communications Option Card Current Draw