WhatsApp: +86 16626708626
Email: 
Phone: +86 16626708626Description
3. Key Technical Specifications
| Parameter | Value |
|---|---|
| Number of Outputs | 16 electronically fused (8 points/group) |
| Voltage Category | 12/24 V DC source |
| Operating Voltage Range | 10…31.2 V DC |
| Current per Point, Max | 1 A @ 60 °C |
| Current per Module, Max | 8 A @ 60 °C |
| Surge Current per Point | 2 A for 10 ms (repeatable every 2 s) |
| Minimum Load Current | 3 mA per point |
| Output Delay (Off → On) | 70 µs nominal / 1 ms max |
| Output Delay (On → Off) | 360 µs nominal / 1 ms max |
| Backplane Current @ 5.1 V | 250 mA |
| Backplane Current @ 24 V | 2 mA |
| Power Dissipation, Max | 4.1 W @ 60 °C |
| Isolation Voltage | 250 V continuous, basic insulation |
| Removable Terminal Block | 1756-TBNH or 1756-TBSH |
| Operating Temperature | 0 °C to +60 °C |
4. Product Introduction
The Allen-Bradley 1756-OB16E is a 16-point DC output module for ControlLogix systems. It provides electronically fused 10–31.2 V DC outputs arranged in two groups of eight points.
Each point is rated 1 A continuous (8 A module total) at 60 °C and includes electronic fusing that opens on overcurrent or short-circuit conditions. The module supports scheduled outputs, configurable fault/program states (Hold Last State, On, or Off), and installs in any 1756 ControlLogix chassis. It is commonly used for solenoid valves, relays, indicators, and other 24 V DC loads requiring point-level protection without external fuses.
5. Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| Output point will not turn on | Electronic fuse tripped or open field circuit | ✅ High | Check point status LED and diagnostic tags in Studio 5000 | Clear fuse fault; verify load wiring and current |
| Entire group offline | Group fuse tripped or common wiring fault | ✅ High | Measure voltage at group common; inspect RTB | Reset module or clear fault; repair common wiring |
| Module OK LED off / faulted | Backplane power or chassis communication issue | ❌ Medium | Verify chassis power and module seating | Reseat module; check chassis power supply |
| Output turns on but load does not energize | Open field wiring or insufficient voltage | ❌ Low | Measure voltage at output terminal under command | Repair field wiring or check field power supply |
| Intermittent output dropouts | Overcurrent or inductive kick | ✅ Medium | Monitor current draw; check for inductive loads without suppression | Add flyback diodes or reduce load current |
| High leakage keeps load partially on | Leakage current + low-power load | ❌ Low | Measure off-state voltage/current | Add bleeder resistor or select different module |
If the fault remains unresolved, capture diagnostic tags, LED status, and field voltage readings before contacting support.
1756-OB16E
1756-OB16E
6. Frequently Asked Questions (FAQ)
Q: Is the 1756-OB16E still in production? Yes. The ControlLogix platform remains active. New and New Surplus units are widely available.
Q: What is the difference between 1756-OB16E and 1756-OB16D? Both are electronically fused. The OB16E is rated 1 A per point; the OB16D is rated 2 A per point. Choose OB16D for higher-current loads.
Q: Does the electronic fuse reset automatically? The fuse can be cleared via software command or by cycling power after the fault is removed. Persistent overloads will re-trip the fuse.
Q: What terminal blocks are required? Use a 1756-TBNH (screw-clamp) or 1756-TBSH (spring-clamp) 36-pin Removable Terminal Block. The module is not compatible with older 20-pin RTBs.
Q: Can I hot-swap the 1756-OB16E? Yes, ControlLogix supports removal and insertion under power (RIUP) when the chassis and system are properly configured. Follow Rockwell safety guidelines.
Q: What is the maximum current the module can supply? 1 A continuous per point and 8 A continuous for the entire module at 60 °C. Exceeding either limit will trip the electronic fuses.
Q: Why is New Surplus sometimes priced lower? These are genuine Allen-Bradley modules from excess inventory or cancelled projects. They are unused and typically supplied with anti-static protection. They are not refurbished unless specifically stated.
