PRODUCT INFORMATION
Product Overview
The Allen-Bradley 1746-NT8 is an SLC 500 Analog Input Module designed for temperature and low-voltage signal monitoring. It provides eight input channels for connecting thermocouple and millivolt sensors. The module converts analog signals to digital values using sigma-delta modulation. Converted data is stored in local memory and retrieved by SLC 500 processors. It installs into standard modular chassis or the 1746-A2 fixed expansion chassis.
The unit draws 120 mA at 5V DC and 70 mA at 24V DC from the backplane. Total maximum backplane power consumption is 2.28 W during operation. Input overvoltage protection is rated at plus or minus 30V DC and 600W pulsed. Field devices connect through the 1746-RT34 removable terminal block. The terminal block includes two cold-junction compensation sensors for thermal accuracy. Nine front green LEDs indicate channel status and operational health.
TECHNICAL DATA
Technical Specifications
| Parameter | Specification |
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| A/D Conversion method | Sigma-delta modulation |
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| Backplane Current | 120 mA @ 5VDC; 70 mA @ 24VDC |
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| Backplane Current (24 Volts) | 70 milliamps |
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| Backplane Current (5 Volts) | 120 milliamps |
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| Backplane Power Consumption | 2.28W maximum (0.6W at 5V dc, 1.68W at 24V dc) |
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| Category | PLCs |
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| Compatible Thermocouple Sensors | J, K, T, E, S, R, B and N |
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| Compatible miliVolt signal | +/- 50 mV and +/- 100 mV |
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| I/O Chassis location | Any slot except Slot 0 |
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| Inputs | 8 |
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| Module Type | Thermocouple/mV Analog Input Module |
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| No. of Inputs | Eight (8) |
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| Open Circuit Detection | Zero; Upscale; Downscale |
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| Operating Temperature | 0 to 60 degrees Celsius |
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| Resolution | 16 bits in, 14 bits out |
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| Step Response | 60 milliseconds in, 2.5 milliseconds out |
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| Storage Temperature | -40 to 85 degrees Celsius |
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| UPC | 611320130881 |
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| Update Time | 356 milliseconds-4.05 seconds |
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| Weight | 0.63 lbs (0.28 kg) |
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TECHNICAL INFORMATION
Features
- Eight chassis-installed input channels receive thermocouple and millivolt signals.
- Sigma-delta analog-to-digital conversion provides 16-bit input and 14-bit output resolution.
- Automatic self-calibration occurs approximately every two minutes after system power-up.
- Supports thermocouple types J, K, T, E, S, R, B, and N.
- Accepts DC millivolt signal ranges of plus or minus 50 mV and 100 mV.
- Nine green LED status indicators show individual channel activity and module status.
- Digital low-pass filter provides selectable programmable filter frequency settings.
- Normal mode and common mode rejection ratings exceed 100 dB at 50 to 60 Hz.
TECHNICAL INFORMATION
Applications
- Direct thermocouple temperature signal monitoring across SLC 500 automation systems.
- Low-voltage millivolt sensor signal acquisition within modular 1746 chassis architectures.
- Thermal data acquisition for PID loop control using SLC 500 controllers.
TECHNICAL INFORMATION
Connections / Interfaces
- Field wiring connects to the 1746-RT34 removable terminal block.
- Two cold-junction compensation sensors provide measurement accuracy within plus or minus 1.72 degrees Celsius.
- Connected field input devices must have an impedance under 100 Ohms to maintain rated accuracy.
- Overall module input impedance exceeds 10 M Ohms.
TECHNICAL INFORMATION
Installation Guidelines
- Mount the module in any chassis slot except slot 0.
- Slot 0 is reserved exclusively for SLC 500 processors or communication adapters.
- Compatible chassis include modular 1746 enclosures and the 1746-A2 fixed expansion chassis.
TECHNICAL INFORMATION
Configuration Guidelines
- Available data formats include engineering units, Scaled for PID, and Proportional counts.
- Scaled for PID is the primary format used with thermocouple and millivolt inputs.
- Open-circuit detection offers selectable zero, upscale, or downscale response behavior.
- Diagnostic bits indicate channel error, open-circuit, under-range, and over-range conditions.
TECHNICAL INFORMATION
Compatibility
- Compatible with SLC 5/01, SLC 5/02, SLC 5/03, SLC 5/04, and SLC 5/05 processors.
- Installs into SLC 500 modular chassis and 1746-A2 fixed style expansion chassis.
TECHNICAL INFORMATION
Compliance and Certifications
- UL approved.
- CUL approved.
COMPATIBILITY
Compatibility & Replacement
COMPATIBLE MODELSCompatible with SLC 5/01, SLC 5/02, SLC 5/03, SLC 5/04, and SLC 5/05 processors. Installs into SLC 500 modular chassis and 1746-A2 fixed style expansion chassis.
Verify compatibility against the exact Part Number, revision and manufacturer documentation before ordering.
PART VERIFICATION
Before You Order
Industrial automation parts can share similar model names, suffixes and revisions. Confirm the complete manufacturer Part Number before purchase.
01Check Part NumberMatch the complete ordering code on the existing unit.
02Confirm RevisionCheck suffix, hardware or firmware when applicable.
03Send a Label PhotoWe can review a clear label photo when identification is uncertain.
ORDERING PROCESS
From RFQ to Dispatch
1Submit Part Number2Verify Product Identity3Confirm Stock & Condition4Issue Quotation5Dispatch & Tracking
PRODUCT FAQ
Frequently Asked Questions
Which sensor types connect directly to the 1746-NT8 module?
The 1746-NT8 supports thermocouple types J, K, T, E, S, R, B, and N. It also accepts DC signals of plus or minus 50 mV and 100 mV.
Which chassis slots accept the 1746-NT8 analog input module?
The module installs into any chassis slot except slot 0. Slot 0 is strictly reserved for processors or communication adapters.
What terminal block is required for connecting field wiring?
Wiring connects through the 1746-RT34 removable terminal block. It includes two cold-junction compensation sensors for accurate temperature measurements.
What data formats are supported by the 1746-NT8?
Supported data formats include engineering units, Scaled for PID, and Proportional counts. Scaled for PID is standard for temperature signals.
