Description
Product Introduction
The Allen-Bradley 1769-OB32 is a high-density, 32-channel digital output expansion module designed for CompactLogix control systems and MicroLogix 1500 controllers. By doubling the output density of standard 16-point cards within a single-slot footprint, it provides an efficient solution for control panels with space constraints and high I/O counts.
Operating on a 24VDC nominal voltage range, the 1769-OB32 delivers sourcing (PNP) solid-state switching across two isolated groups of 16 outputs. It utilizes a high-density wiring setup (typically paired with a 1769-RTBN18/40-pin terminal block or pre-wired IFM cable assemblies) to connect a full 32-point output field array without taking up valuable DIN rail space.
Key Technical Specifications
| Parameter | Value |
| Outputs Per Module | 32 Sourcing (PNP) Solid-State Outputs |
| Operating Voltage Range | 20.4VDC to 26.4VDC |
| Output Current Capacity | 0.5 A per channel @ 60°C (4.0 A max per group / 8.0 A total module) |
| Output Groups | 2 Isolated Groups (16 Channels per group: Group 0: 0–15, Group 1: 16–31) |
| Off-State Leakage Current | 1.0 mA max per channel |
| On-State Voltage Drop | 1.0VDC max @ 0.5 A |
| Power Distance Rating | 6 Modules (Must be mounted within 6 slots of power supply) |
| Backplane Current Draw | 300 mA @ 5.1VDC | 2.0 mA @ 24VDC |
| Response Time | Turn-ON: 0.1 ms | Turn-OFF: 1.0 ms |
| Wiring Connection | 40-Pin Terminal Block (1769-RTBN40) or Quick-Bus IFM Cables |
Application Scenarios & The “Trench” Experience
The Trench Story
It is 11:30 PM on a cabinet upgrade retrofit for a high-speed automotive stamping cell. Panel real estate is tight, and you have to fit 64 new 24VDC pilot valve outputs into a junction box that originally only had room for two 16-channel cards. Trying to squeeze four traditional 16-point modules onto the DIN rail would force you to mount an extra expansion bank and buy an expensive cable bridge adapter. Swapping the planned cards out for two 1769-OB32 32-channel modules doubles the output density in half the panel width. Paired with pre-wired A-B IFM terminal block cables, you land 32 outputs per slot in minutes, clear the backplane distance checks cleanly, and wrap up wiring hours ahead of morning testing.
Specific Applications
- High-Density Valve Manifolds: Drives multiple 24VDC pneumatic solenoid valves directly across automated packaging machinery.
- Large Alarm & Indicator Light Arrays: Controls plant floor stack lights, status annunciators, and visual panel indicators.
- Interfacing with Remote Relay Panels: Triggers intermediate 24VDC interposing relay coils across conveyor transfer hubs.
- Packaging & Sorting Diverters: Actuates high-speed sorting gates requiring fast response times (sub-millisecond turn-on).
- 1769-OB32
- 1769-OB32
- 1769-OB32
Transparency SOP: Quality Assurance & Testing
Every 1769- module undergoes a thorough quality audit and electrical functional test prior to shipment:
- Physical & Terminal Block Inspection: We inspect the side backplane locking levers, check backplane bus pins for damage, and verify that terminal retention clips seat securely.
- Backplane Logic Power Up: The card is installed in a CompactLogix rack to verify proper power draw, module recognition in Studio 5000, and backplane health.
- 32-Channel Load-Bank Sweep: We connect an automated 24VDC load test rig across all 32 outputs, firing each channel individually and in full-group patterns to verify current switching under load (0.5A per channel).
- Leakage & Voltage Drop Test: On-state voltage drop is measured to confirm it remains below 1.0VDC, and off-state channels are verified for clean shutdown with zero leakage false-triggering.
- Thermal & Isolation Verification: We verify optical isolation between Group 0 and Group 1 to confirm no cross-talk or short circuits between distinct DC power feeds.
The Veteran’s Tech Trap Guide
- ⚠️ Watch Out for Sourcing (PNP) vs. Sinking (NPN): The 1769- is a Sourcing output module. It supplies +24VDC to your load (the other side of your load must connect to DC Common/0V). If your field devices require a Sinking card that switches to ground/DC Common, you need the 1769-OV32 module instead.
- ❗ Mind the 6-Slot Power Distance Rule: The 1769- has a power distance rating of 6. It must be installed within 6 slots of a 1769 system power supply (such as a 1769-PA4 or 1769-PB4). Placing it further down the backplane causes logic dropouts due to 5VDC backplane voltage drops.
- ⚠️ Respect Group Current Limits (4.0 A Max): While each point supports up to 0.5 A, the maximum rating for an entire 16-channel group is 4.0 A total. Turning on all 16 channels in a group simultaneously at full 0.5 A load will pull 8.0 A, tripping internal thermal protection or damaging the module.
- ❗ Use the Right Terminal Block / Wiring Harness: Because of its high pin density, the 1769- cannot use standard 18-pin 1769-RTBN18 terminal blocks. It requires either the 1769-RTBN40 40-pin screw terminal block or a pre-wired Allen-Bradley 1492-CABLE system.
Frequently Asked Questions
Q: What is the primary difference between the 1769-OB16 and the 1769-?
The 1769- offers 32 sourcing outputs in a single slot using a 40-pin wiring connector, double the output density of the 16-channel 1769-OB16 (which uses an 18-pin removable terminal block).
Q: Does the 1769- require external 24VDC power connected to the module?
Yes. The backplane only provides low-voltage logic power. You must supply external +24VDC and DC Common to the module’s VDC and DC COM terminals for each isolated output group to drive field loads.
Q: Can I mix different power sources on Group 0 and Group 1?
Yes. Group 0 (Outputs 0–15) and Group 1 (Outputs 16–31) are galvanically isolated from each other. You can feed Group 0 from one 24VDC supply and Group 1 from an independent 24VDC supply if required.
Q: What happens if an output experiences a short circuit in the field?
The 1769- features built-in electronic short-circuit protection. If a channel experiences an overcurrent or short-circuit condition, the module automatically shuts down that output driver to protect internal circuitry.
Q: Is the 1769- compatible with CompactLogix 5370 L1, L2, and L3 processors?
The 1769- can be used directly as local or expansion I/O on 1769 CompactLogix L3 processors (e.g., 1769-L33ER, 1769-L35ER) and L2 processors that support right-side 1769 expansion modules. L1 processors use 1734 POINT I/O instead.
Q: What warranty is included with your surplus or refurbished 1769- cards?
Every 1769- module we ship includes our full 12-month replacement warranty. If a hardware fault occurs under normal operating conditions within 365 days of purchase, we replace the unit immediately from stock or issue a full refund.
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