Application Scenarios
A water-treatment plant needed to maintain precise control of chemical dosing, even when the SCADA system was temporarily unavailable. The original analog output module had become unstable, causing small fluctuations in the control signal sent to a dosing-pump inverter. The control logic was still valid, but the physical interface could no longer hold a steady output.Technicians installed a tested Allen-Bradley 1746-N04I in an available SLC 500 chassis slot. They calibrated the four output channels, reassigned the control variables and performed a step-response test from 4mA to 20mA. The plant then monitored both the controller command and the actual pump output to confirm that the control loop was stable.The value of the 1746-N04I was not limited to adding analog outputs. It restored predictable communication between the SLC 500 program and the field instrument. For a legacy system that still performs reliably, that can be more valuable than an immediate and costly control-platform replacement.
Parameter
| Main Parameters | Value / Description |
|---|---|
| Product Model | 1746-N04I |
| Manufacturer | Allen-Bradley, a Rockwell Automation brand |
| Product Category | Analog output module |
| Control Platform | SLC 500 |
| Number of Channels | 4 independently configurable current output channels |
| Output Signal | 4–20mA current loop |
| Output Type | Current sourcing / active 4–20mA output |
| Resolution | 16 bits plus sign |
| Data Format | Integer |
| Conversion Type | D/A conversion from SLC 500 output data |
| Accuracy | ±0.2% full scale at 25°C; ±0.5% full scale over the operating temperature range |
| Maximum Load Resistance | 750Ω at 20mA |
| Open-Circuit Detection | Detected and reported for each channel |
| Short-Circuit Detection | Detected and reported for each channel |
| Update Method | On command or change of state |
| Backplane Current Draw | 200mA at 5V DC |
| Power Dissipation | 3.9W |
| Isolation | 1500V AC between analog outputs and backplane for 1 second |
| Communication Circuit Isolation | 500V DC |
| Status Indicators | Module status, fault and per-channel status LEDs |
| Terminal Type | Removable screw terminal block |
| Mounting Method | Single-slot module in a compatible 1746 chassis |
| Slot Position | Any available I/O slot; the processor slot is not used for ordinary I/O |
| Chassis Compatibility | 1746-A4, 1746-A7, 1746-A10 and 1746-A13 chassis, subject to system capacity |
| Programming Software | RSLogix 500 |
| Dimensions | 144.5 × 34.6 × 130.2mm |
| Weight | 0.27kg |
| Operating Temperature | 0°C to +60°C |
| Storage Temperature | −40°C to +85°C |
| Relative Humidity | 5% to 95%, non-condensing |
| Certifications | UL, CSA and CE; confirm exact approvals on the supplied unit |
| Lifecycle Status | Discontinued; Rockwell Automation standard support ended on 30 September 2024 |
| Replacement Category | Engineering replacement |
Reviews
There are no reviews yet.