Figure 17: Hart / 4-20Ma Operating Voltage (Vdc) - Honeywell SLG 700 Quick Start Manual

Figure 17: HART / 4-20 mA Operating Voltage (VDC)
See the SLG 700 User's Manual, Document #34-SL-25-11 for details on the voltage
calculation, and guidance when considering the resistance of intrinsic safety barriers.
Loop wiring is connected to the Transmitter by simply attaching
the positive (+) and negative (–) loop wires to the first two
terminals on the left, marked with LOOP+ and LOOP- on the
transmitter body in the Electronic Housing as shown in Figure
18. The third terminal to the right is a TEST terminal and is only
used for loop current diagnostics / measurements.
TIP: A current measurement device with low internal resistance
(< 10ohms) can be connected between the TEST terminal "+"
and the TEST terminal "-" of the Transmitter Terminal Block to
acquire a readout of the loop current.
Loop current wiring should never be connected to the TEST "+"
terminal. This can damage the Transmitter.
Additionally, never connect the current measurement device
CAUTION
between the Loop "+" terminal and the TEST "+"terminal. This
also will damage the Transmitter.
28 Quick Start Installation Guide December 2017