Spectrum Controls 140 EHC 204 00sc - Manual (Page 20)

Counter / Flow Meter Input Module
21
Specification Value
Wire Type Stranded, Cu-90°C (194°F)
Wire Size 16 to 22 AWG
Terminal Screw Torque 0.68 Nm (6 in-lb)
Retaining Screw Torque 0.46 Nm (4.1 in-lb)
To wire the terminal block:
1. Determine the length of cable you need to connect a channel to its field device. Remember to include
additional cable to route the drain wire and foil shield to their ground points.
2. If you need to remove the terminal block cover, insert a screwdriver into one of the square wiring holes,
and gently pry the cover off. Be sure to replace the cover before proceeding.
3. Loosen the terminal screw to be wired.
4. Route the wire under the terminal pressure plate.
5. Connect only one end of the shield to the module. You can use the bare wire or a spade lug. The
terminals accept a 6.35 mm (0.25 in.) spade lug.
6. Tighten the terminal screw, making sure the pressure plate secures the wire.
7. A removable write-on label (ID tag) is provided with the terminal block. Remove the label from the
door, mark the identification of each terminal with permanent ink, and slide the label back into the door.
The ID tag is visible when the module door is closed.
Wiring the Module for Inputs
After the terminal block is wired, use the procedure in this section to connect the inputs to the terminal block.
To ensure proper operation and high immunity to electrical noise, always use Belden 8761 shielded, twisted-pair
wire, or equivalent.
CAUTION - To prevent shock hazard, take care when wiring the module to analog signal sources. Before
wiring, disconnect power from the system power supply and from any other source.
CAUTION - When wiring an analog input, take care to avoid connecting a voltage source to a channel
configured for current input. Improper module operation or damage to the voltage source can occur.
1. At each end of the first cable, strip some casing to expose the individual wires.
2. On each end of the cable, separate the wires and trim the signal wires to 5.08 cm (2 in.) lengths. Strip
about 4.76 mm (.18 in.) of insulation to expose the end of each wire. Be sure to not cut the wires too
short.