1746-NR8 Resistance Temperature Detector (RTD)/Resistance module The direct resistance is 0-150 ohms

The 1746-NR8 is a resistance temperature detector (RTD)/resistance module. The module accepts resistance signals from RTD sensors such as Platinum (385) 100, 200, 500 and 1000; Platinum (3816) 100, 200, 500 and 1000; Copper (426) 10, nickel (618) 120, nickel (672) 120 and nickel-iron (518) 604 have direct resistance values of 0-150 ohms, 0 to 500 ohms, 0 to 1000 ohms and 0 to 300 ohms.

This module is specifically designed for SLC 500 systems. It can be used specifically for two (2) variants of the SLC 500, such as fixed and modular hardware styles. It occupies a single slot in any used chassis and does not require an external power supply, but is powered by a backplane power supply generated by the system power supply.

The module is mainly used for temperature applications, as the RTD sensor is specifically used to measure temperature readings. The resistance capability of the module is suitable for measuring displacement or motion or mechanical devices. Typically, it is used to measure the length of the stroke, and the movement is reflected in the decrease and increase in the resistance reading.

The module supports 2-wire, 3-wire, and 4-wire RTD sensors. For 2-wire RTDS, the recommended wire is the Belden 9501 shielded cable or equivalent cable. For 3-wire or 4-wire RTDS, use the Belden 9533 or Belden 83503 cable. For 2-wire RTDS, avoid cables that are too long, as this can reduce measurement accuracy. This is unavoidable, and by using a lower specification cable (such as AWG #16 wire instead of AWG #24) the impact or long wire can be minimized. Basically, use a cable with lower resistance per foot. Detachable terminal (RTB) terminals are only used for single-wire connections.

Channel status can be monitored by LED indicators, while module operation can be monitored by LED status indicators. The module has a low-pass digital filter and a programmable input filter. The analog-to-digital conversion of this module is sigma-δ modulation. Every time the module is powered on, its automatic calibration process occurs, which can also be programmed to a specific cycle every 5 minutes. The RTD types on the 1746-NR8 module include copper, platinum, nickel-iron, and nickel. The terminal compatible with this module is the Allen-Bradley 1746-RT-35 terminal.

The backplane of the 1746-NR8 module has a maximum power consumption of 1.82 W, 0.5 W at 5 V DC, and 1.32 W at 24 V DC. The backplane current consumption of the 1746-NR8 is 100 mA at 5 V DC and 55 mA at 24 V DC. Its maximum common-mode voltage is +/ -1 V, while its maximum permanent overload is +/ -5 mA (current) and +/ -5 V DC. The isolation voltage of the 1746-NR8 module is continuously present at 5 volts DC between channels and 500 volts AC between input and backplane and between input and chassis ground for 1 minute. Its operating temperature range is 32 to 140 degrees Fahrenheit, storage temperature range is -40 to 185 degrees Fahrenheit, and non-condensing relative humidity is 5 to 95 percent.