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Manufacturer | Rockwell Automation |
Brand | AB |
Part Number/Catalog No. | 1746-NT8 |
Series | SLC 500 |
Inputs | 8 |
Module Type | Thermocouple/mV Analog Input Module |
Backplane Current (5 Volts) | 120 milliamps |
No. of Inputs | Eight (8) |
Backplane Current (24 Volts) | 70 milliamps |
Compatible Thermocouple Sensors | J, K, T, E, S, R, B and N |
Update Time | 356 milliseconds-4.05 seconds |
Compatible miliVolt signal | +/- 50 mV and +/- 100 mV |
Backplane Current | 120 mA @ 5VDC; 70 mA @ 24VDC |
Resolution | 16 bits in, 14 bits out |
Backplane Power Consumption | 2.28W maximum (0.6W at 5V dc, 1.68W at 24V dc) |
Step Response | 60 milliseconds in, 2.5 milliseconds out |
Step Response | 60 milliseconds in, 2.5 milliseconds out |
Open Circuit Detection | Zero; Upscale; Downscale |
UPC | 10611320130888 |
I/O Chassis location | Any slot except Slot 0 |
Operating Temperature | 0 to 60 degrees Celsius |
Storage Temperature | -40 to 85 degrees Celsius |
A/D Conversion method | Sigma-delta modulation |
About 1746-NT8
The 1746-NT8 is an SLC 500 Thermocouple/mV Analog Input Module by
AB. It is an Eight (8) channel chassis installed module which
receives thermocouple/mV signal which is digitally converted for
retrieval by any SLC 500 processors. It has a backplane rating of
120mA at 5V DC and one of 70mA at 24V DC with an overall backplane
power of 2.28W. The 1746-NT8 uses a Delta-Sigma signal conversion
method and it has a digital low pass filter with selectable
programmable filter frequencies. Its normal mode rejection
frequency between the terminals is greater than 100dB at 50-60 Hz
and its common mode rejection frequency between inputs and ground
is also above 100dB at 50-60 Hz. The 1746-NT8 module automatically
calibrates itself from power approximately every 2 minutes after
power up. It offers input overvoltage protection at +/-30V DC and
600W pulsed for 1ms and provides 12.5V DC circuit isolation tested
at 500V DC for 1 minute between inputs and the chassis ground and
between the inputs and backplane.
The 1746-NT8 has 9 green LED lights that indicate a channel status
and the module’s status. It uses the 1746-RT34 (RTB) removable
terminal block for connection input devices. Included with the
terminal block are Two (2) cold-junction compensation (CJC) sensors
with an accuracy of +/-1.72 deg. Celsius. The 1746-NT8 has various
selectable input types and the with an overall input impedance is
greater than 10 M Ohms. Any input devices connected to it must have
an impedance of fewer than 100 Ohms to meet the accuracy level. The
1746-NT8 offers a selectable open-circuit detection with 1 cycle
per channel and an overall input stem response time of 400ms. The
module has a functional temperature range between 0 deg. Celsius
and 60 deg. Celsius at 5-95% humidity without condensation and is
UL and CUL-approved.
The 1746-NT8 is an analog input module that belongs to the SLC 500
product family. This module is specifically a Thermocouple /
millivolt that is compatible with SLC 500 processors such as SLC
5/01, 5/02, 5/03, 5/04 and 5/05. It may be used with SLC fixed
style or modular hardware category.
Similar to other analog input modules, the 1746-NT8 converts the
receive analog signal to a digital value using Sigma-Delta
modulation. The converted data is save to the module’s local memory
which is communicated to the CPU for creating a data table where
the digitally converted values are stored.
This module may be installed in a fixed style chassis specifically
using a 1746-A2 chassis. If used with a modular style controller,
this module may be installed in any slot except slot 0. Slot 0 is
always reserved for the controller or communication adapters such
as a Remote IO, Data Highway Plus (DH+) and Ethernet communication
module.
The data formats available for the input signal include engineering
units, Scaled for Proportional-Integral-Derivative (PID) and
Proportional counts. Scaled for PID is the most compatible data
format for Thermocouple and millivolt input signals.
This module is capable of detecting Open circuit, Under-Range,
Over-Range and Channel Error. These error alarms are assigned with
specific bits that may be accessed by monitoring systems such as
Human Machine Interface (HMI) and Supervisory Control and Data
Acquisition (SCADA) systems. These bits are included in the data
table that is created when the module is configured using the
RSLogix 500 programming software.