July 2017
STT700 Quick Start Installation Guide
9
Wiring Variations
The above procedures are used to connect power to a transmitter. For loop wiring and
external wiring, detailed drawings are provided for transmitter installation in
non-intrinsically safe areas and for intrinsically safe loops in hazardous area locations.
This procedure shows the steps for connecting power to the transmitter.
Grounding and Lightning Protection
Connect a wire from the mounting screws to earth ground to make the protection
effective. Use a size 8 AWG or (8.37mm2) bare or green covered wire for this
connection. For ungrounded thermocouple, mV, RTD or ohm inputs, connect the input
wiring shield(s) to the same earth ground connection. For grounded thermocouple
inputs, connect the internal ground connection shown in
Figure 8
to the same earth
ground as used by the thermocouple. As noted above, the loop power wiring shield
should only be connected to earth ground at the power supply end.
For DE, the burnout direction needs to be selected in the hardware and this will be
detected at power on time.
Input Sensor Wiring
Connect the input sensors as shown in
Figure 9
below: RTD Thermocouple, mV, Ohm
and Millivolt connections.
Figure 9: HART/DE Input Wiring Diagram for single sensor connection