Spectrum Controls 1769sc-HART Modules User Manual
Page 27
Chapter 3: Installation and Wiring
User's Manual 0300215-03 Rev. A
3-9
NOTE: The terminal screws are non-captive. Therefore, it is possible to use a ring lug
[maximum 1/4 inch o.d. with a 0.139 inch minimum i.d. (M3.5)] with the module.
3.
Tighten the terminal screw making sure the pressure plate secures the wire.
Recommended torque when tightening terminal screws is 0.68 Nm (6 in-lbs).
NOTE: If you need to remove the finger-safe cover, insert a screwdriver into one of the
square, wiring holes and gently pry the cover off. If you wire the terminal block with
the finger-safe cover removed, you may not be able to put it back on the terminal block
because the wires will be in the way.
Wire Size and Terminal Screw Torque
Each terminal accepts up to two wires with the following restrictions:
Wire Type
Wire Size
Terminal Screw
Torque
Retaining Screw
Torque
Solid Cu-90°C
(194°F)
#14 to #22 AWG
(1.63 to 0.65 mm)
0.68 Nm (6 in-lbs)
0.46 Nm (4.1 in-lbs)
Stranded Cu-90°C
(194°F)
#16 to #22 AWG
(1.63 to 0.65 mm)
0.68 Nm (6 in-lbs)
0.46 Nm (4.1 in-lbs)
!
Attention
Use supply wires suitable for 20°C above surrounding ambient.
3.7.5
Wiring the Module
!
Attention
To prevent shock hazard, care should be taken when wiring the module
to analog signal sources. Before wiring any module, disconnect power
from the system power supply and from any other source to the module.
After the module is properly installed, follow the wiring procedure below, using the
proper cable, Belden 8761.
Figure 3-6
To wire your module follow these steps.
1.
At each end of the cable, strip some casing to expose the individual wires.
2.
Trim the signal wires to 2-inch (5 cm) lengths. Strip about 3/16 inch (5 mm) of
insulation away to expose the end of the wire.
!
Attention
Be careful when stripping wires. Wire fragments that fall into a module
could cause damage at power up.
3.
At one end of the cable, twist the drain wire and foil shield together, bend them away
from the cable, and apply shrink wrap. Then earth ground at the preferred location
based on the type of sensor you are using. See Grounding for more details.
4.
At the other end of the cable, cut the drain wire and foil shield back to the cable and
apply shrink wrap.