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Reference Manual
00809-0100-4444, Rev AC
Section 2: Quick Installation and Start-Up
January 2015
Quick Installation and Start-Up
2.12.5 Analog output
The analog output signal is a 4-20mA current loop. The loop can be powered internally or
externally via a hardware switch located on the front of the electronics stack. The switch is set to
internal power when shipped from the factory. For units with a display, the LOI must be removed
to change switch position.
Intrinsically safe analog output requires a shielded twisted pair cable.
For HART communication a minimum loop resistance of 250 ohms is required. It is
recommended to use individually shielded twisted pair cable. The minimum conductor size is
0.51 mm diameter (#24 AWG) for cable runs less than 5,000 feet (1,500m) and 0.81 mm
diameter (#20 AWG) for longer distances.
Internal power
The 4-20mA analog signal is a 24VDC active output.
Maximum allowable loop resistance is 500 ohms.
Wire terminal 1 (+) and terminal 2 (-). See Figure 2-22.
Figure 2-22. Analog Wiring—Internal Power
NOTICE
Terminal polarity for the analog output is reversed between internally and externally
powered.