Spectrum Controls 1769sc-IF8u - Manual (Page 22)

12 Compact IO ™ Universal Input module
Step 3: Wire the module. Reference
Chapter 3
(Installation and Wiring)
Follow the guidelines below when wiring the module.
General
• Power and input wiring must be in accordance with Class 1, Division
2 wiring methods, Article 501-4(b) of the National Electric Code,
NFPA 70, and in accordance with the authority having jurisdiction.
• Channels are isolated from one another by ±10V dc maximum.
• Route field wiring away from any other wiring and keep it as far as
possible from sources of electrical noise, such as motors,
transformers, contactors, and ac devices. As a general rule, allow at
least 15.2 cm (6 in.) of separation for every 120V of power.
• Routing field wiring in a grounded conduit can reduce electrical noise.
• If field wiring must cross ac or power cables, ensure that they cross
at right angles.
• If multiple power supplies are used with analog millivolt inputs, the
power supply commons must be connected.
Terminal Block
• Do not remove the CJC sensor from the terminal block if
thermocouples are to be utilized. Removal of the sensor will reduce
accuracy.
Note: For improved accuracy, use a remote terminal block
configuration when possible. See chapter 3 for more details.
• For millivolt and current sensors, use Belden 8761 shielded, twisted-
pair wire (or equivalent) to ensure proper operation and high immunity
to electrical noise.
• For RTD and resistance sensors, use Belden 9501 (2 wire), 9533 (3
wire) and 83503 ( for runs over 100 feet) or equivalent.
• For a thermocouple, use the shielded, twisted-pair thermocouple
extension lead wires specified by the thermocouple manufacturer.
Using the incorrect type of thermocouple extension wire or not
following the correct polarity will cause invalid readings.