Eaton Cutler Hammer MN05001002E Installation Manual

Intelligent Technologies QCPort System Install ManualNovember 2005MN05001002E For more information visit www.eatonelectrical.com Page 26Appendix A: Using Long Run CablesWhen devices require locating further than 100 feet [30 meters] from one another, thephysical media changes from QCPort Interconnects to Long Run cables. This cable isbetter rated for current carrying capacity and for the RS485 communication.When connecting between Long Run and a QCPort device, the D77E-QPLR is requiredto change the physical media. The D77E-QPLR provides for screw lugs for connection toindustrial RS485 cable.Example of Long Run Cable: One Power Supply (End-Connected)The following example uses the full calculation method to determine the configuration forone end-connected power supply on a thick cable trunk line.• Device 1 and Device 2 cause the same voltage drop, but Device 2 is twice as farfrom the power supply and draws half as much current.• Device 4 draws the least amount of current, but it is farthest from the powersupply and causes the greatest incremental voltage drop.Figure 13 : Example of Long Run Cable: One Power Supply (End-Connected)Device 11.0 ADevice 20.5 ADevice 30.4 ADevice 40.3 ATT95 ft18 ft36 ft43 ftT – Biasing resistorPowerSupply

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