1746-N041

Overview of Allen Bradley 1746-NO4I

The Allen Bradley 1746-NO4I is a four-channel analog output module designed for the SLC 500 programmable controller platform. This module delivers precise current output control across four independent channels, making it ideal for process automation and industrial control systems that require accurate analog signal generation. The 1746-NO4I features a 14-bit digital-to-analog converter, providing fine resolution for smooth control of field devices such as variable frequency drives, pneumatic valves, and other current-controlled actuators. The module supports multiple current ranges including 0-20 mA and 4-20 mA, the industry-standard signals for process instrumentation. With a maximum backplane current draw of 55 mA at 5 Volts DC and 195 mA at 24 Volts DC, the module integrates efficiently into existing SLC 500 chassis configurations. The 1746-NO4I includes an SW1 power selector switch, allowing users to choose between backplane power or external 24-volt supply based on system requirements and available power budget.

Key Features of Allen Bradley 1746-NO4I

• Four independent current output channels for flexible signal distribution
• 14-bit resolution with output coding from 0 to 32,764 counts at 0-21 mA range
• 2.5 millisecond step response time for fast control applications
• Configurable current ranges: 0-20 mA and 4-20 mA standard process signals
• Dual power options via SW1 switch for backplane or external 24V DC supply
• Operating temperature range: 0°C to 60°C for industrial environments

Technical Specs of 1746-NO4I

Number of Outputs	4 channels
Output Type	Current (non-isolated)
Output Range	0-21 mA (includes 0-20 mA, 4-20 mA)
Resolution	14-bit (2.56348 µA/LSB)
Output Coding	0 to 32,764 counts
Backplane Current	55 mA @ 5V DC, 195 mA @ 24V DC
Step Response	2.5 milliseconds
Operating Temp	0°C to 60°C

Applications / Use Case

The 1746-NO4I analog output module serves critical roles in process control and machine automation environments where precise current signal generation is required. Common applications include controlling pneumatic actuators and positioners in packaging lines, where the 4-20 mA signal adjusts valve positions for filling operations. In chemical processing plants, the module drives variable frequency drives to regulate pump speeds and maintain consistent flow rates. The module is also employed in HVAC systems to modulate damper positions and control temperature loops. Manufacturing facilities use the 1746-NO4I to interface with analog instrumentation such as chart recorders and process indicators. The fast 2.5-millisecond response time makes it suitable for dynamic control loops in hydraulic press applications and molding machines where rapid signal adjustments are necessary. System integrators appreciate the flexible power configuration, which allows the module to operate from either backplane or external power sources depending on chassis loading and application requirements. When installed in SLC 500 systems, the module should be positioned away from high-voltage AC modules to minimize electrical noise interference.

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