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Phone: +86 16626708626Description
Key Technical Specifications
| Parameter | Specification |
| Module Type | Discrete Digital Transistor Output Module |
| Number of Outputs | 16 points |
| Output Category | 24V DC Sourcing (Provides current to sinking field loads) |
| Operating Voltage Range | 10 to 30V DC |
| Backplane Current Consumption | 280 mA at 5V DC (0 mA at 24V DC) |
| Continuous Current per Point | 0.5 A at 30 \textdegree C / 0.25 A at 60 \textdegree C |
| Continuous Current per Module | 8.0 A at 30 \textdegree C / 4.0 A at 60 \textdegree C |
| Surge Current per Point | 3.0 A for 10 ms (repeatable every 1 second) |
| Signal Delay (Max) | ON delay: 0.1 ms | OFF delay: 1.0 ms |
| Isolation Rating | 1,500V AC for 1 minute (Field-to-Backplane) |
Product Introduction & Supply Chain Strategy
The Allen-Bradley 1746-OB16 is a high-density 16-point DC sourcing transistor output card for the SLC 500 control platform. It switches 24V DC field loads—such as solenoid valves, indicator lights, relay coils, and motor starter contactors—directly from 1746 backplane logic commands.
Because Rockwell Automation has officially retired the SLC 500 family, maintaining uncommissioned New Surplus 1746-OB16 stock is critical for protecting legacy automation racks against unexpected downtime. Sourcing genuine New Surplus ensures factory-fresh solid-state switching junctions and zero thermal fatigue, bypassing the high failure rates and output trace degradation common in second-hand pull-outs.
Installation & Configuration Guide
Stage 1: Pre-Installation (Prep & Safety)
- Perform Lock-Out/Tag-Out (LOTO) procedures on the 1746 chassis power supply and field load power sources.
- Put on a properly grounded ESD wrist strap before handling the replacement card.
- Photograph the existing removable terminal block (RTB) wiring to preserve terminal-to-load connections.
Stage 2: Removal
- Loosen the top and bottom retaining screws on the RTB and carefully pull it straight off the 1746-OB16 front header.
- Depress the upper and lower module release latches on the SLC 500 chassis frame simultaneously.
- Slide the card straight out of the slot along its chassis guide rails to avoid bending backplane pins.
Stage 3: Installation (Clone & Seat)
- Verify the replacement 1746-OB16 slot location corresponds with the output table addresses in RSLogix 500.
- Align the circuit board edges with the top and bottom guide tracks of the target 1746 chassis slot.
- Push the module firmly into the slot until both upper and lower release latches snap into place securely.
- Align the pre-wired RTB onto the front terminal header and tighten the retaining screws to 0.5 N·m (4.4 lb·in).
Stage 4: Power-On & Testing
- Re-energize the 24V DC field load supply and verify voltage across terminal
VDCandDC COMconnections. - Apply power to the 1746 rack power supply and observe the front status LEDs:
- Output Status LEDs (0–15): Toggle output bits in the processor program to verify corresponding LED illumination and field device actuation.
- Access RSLogix 500 online mode, navigate to the Output Data Table (
O:e.0/0throughO:e.0/15, whereeis the slot number), and test individual output bit operations.
1746-OB16
1746-OB16
Firmware/Software Versions & Upgrade Notes
- Hardware Compatibility: Series A, B, and C 1746-OB16 modules function identically in all standard SLC 500 chassis racks (1746-A4, A7, A10, A13).
- RSLogix 500 Setup: The 1746-OB16 is a fixed discrete module requiring no firmware flash files or special parameter setup. Select
1746- 16-Output (10/30VDC) Sourcein the I/O Configuration tree. - Firmware Notes: Discrete output cards utilize dedicated solid-state switching transistors and contain no field-upgradable firmware. Hardware replacement is completely plug-and-play.
Frequently Asked Questions (FAQ)
Q: Is this 1746- module a Brand New Surplus unit or a refurbished part?
A: This product is a Brand New Surplus unit. It is not used, not pulled from a decommissioned plant, and not refurbished. All modules undergo rigorous quality verification to ensure OEM-level reliability.
Q: What is the risk of purchasing a cheaper refurbished 1746- card?
A: Refurbished transistor output modules frequently suffer from thermal stress on switching FETs, trace damage caused by prior overcurrent events, or loose terminal header pins. A shorted output transistor can lock a solenoid valve in the ON position, creating severe operational and safety hazards. Investing in New Surplus provides factory-grade reliability and 10 to 15 years of expected service life.
Q: How do you verify the quality and condition of legacy 1746- stock?
A: Every card undergoes our inbound SOP quality verification: inspecting original factory anti-static packaging, verifying zero backplane insertion wear, checking terminal header pins, and performing live 24V DC output load switching tests on an SLC 500 test chassis.
Q: What does “Sourcing Output” mean for field wiring on the 1746-?
A: Sourcing outputs supply 24V DC current out of the module terminals to the field load. The other side of the field load must be connected to 24V DC Common.
Q: Is it safe to hot-swap the 1746- card while the PLC system is under power?
A: No. Allen-Bradley SLC 500 chassis backplanes do not support Hot-Swapping (RIUP). Pulling or inserting any 1746 module while backplane power is active causes arcing that can destroy the card, adjacent I/O cards, or the central CPU. Always disconnect chassis power first.
Q: What warranty coverage comes with this New Surplus 1746-?
A: All 1746- New Surplus units include our comprehensive 1-year replacement warranty. If any output channel or internal circuit fails under standard operating conditions, we will immediately issue a replacement card or full refund.
