1734-OB8E — POINT I/O 8-Point 24V DC Protected Sourcing Output Module

The 1734-OB8E is an 8-point sourcing (PNP) 24V DC transistor output module for the 1734 POINT I/O system with individual electronic protection and diagnostic reporting per point. The "E" denotes protected outputs — each of the eight points has its own short-circuit and overload protection circuit that shuts down only the faulted point and reports a diagnostic bit back to the controller. The other seven outputs continue operating unaffected. At 2A per point, the module handles a wider range of field devices than standard 0.5A POINT I/O output modules.

Specifications

Parameter	Value
Part Number	1734-OB8E
Platform	POINT I/O (1734)
Output Points	8
Output Type	Sourcing (PNP) transistor
Output Voltage	24V DC (10–30V)
Output Current per Point	2 A continuous
Electronic Protection	Per point — short circuit and overload
Fault Reporting	Per-point diagnostic bits in I/O data
Auto-Reset	Yes — when fault condition clears
Leakage Current (OFF)	0.5 mA max
ON-State Voltage Drop	0.4V DC max
Backplane Current (5V)	75 mA
Operating Temperature	−20°C to 55°C
Standards	UL 508, CE, IEC 61131-2

Per-Point Protection and Diagnostics

Standard POINT I/O output modules protect at the group level — a fault on one point shuts down all eight points in the group. Diagnosing which of eight outputs caused the trip requires checking the field wiring manually. The 1734-OB8E changes this: each point has its own protection circuit. A short circuit on Output 3 trips Output 3 only. Outputs 0, 1, 2, 4, 5, 6, and 7 stay on. Simultaneously, the diagnostic bit for Output 3 sets in the controller's I/O tag data, identifying the specific point.

In a controller program, the diagnostic bits can be mapped to HMI alarm tags that display the output number and associated device name directly. A maintenance technician gets to the right terminal in the field without a panel walkdown — the HMI tells them exactly which output tripped and which device is wired to it. This reduces fault-to-repair time meaningfully, especially in distributed POINT I/O nodes where the faulted device may be at a remote location on the machine.

The auto-reset behavior means the protected output re-energizes automatically once the fault condition clears. If the short circuit is persistent (a pinched cable that remains grounded), the output cycles off until the fault is removed. If the trip was transient — a brief inrush from a solenoid or a momentary wiring issue — the output recovers without operator intervention. For applications where automatic restart after a fault clear is unacceptable, the program logic should monitor the diagnostic bit and hold the output off until an operator acknowledgment clears the fault latch.

2A per Point — Loads This Module Handles Directly

At 2A continuous per point, the 1734-OB8E drives loads that a standard 0.5A POINT I/O output module can't handle without an interposing relay:

Direct-acting solenoid valves in the 1/2-inch and 3/4-inch size range (typically 0.8–1.5A at 24V DC)
24V coil contactors for motor starters up to approximately 15 kW
Incandescent or resistive heater indicator lamps to 48W at 24V
Multiple LED indicator strings in parallel (30–50 mA each, up to 40+ LEDs per point)
24V DC brake coils for servo motor holding brakes

The combination of 2A capacity and per-point fault protection means high-current loads can connect directly to POINT I/O outputs without external relays, while preserving the diagnostic visibility that identifies a failed load or wiring fault by point number.

FAQ

Q: What POINT I/O adapters are compatible?

All standard 1734 adapters — EtherNet/IP (1734-AENT), DeviceNet (1734-ADN), ControlNet (1734-ACN), and others. The output module communicates through the POINT I/O backplane regardless of the network adapter at the node head.

Q: Does the per-point protection replace the need for external fusing?

No. The electronic protection protects the module's output transistors — it is not a branch circuit protection device. External fusing or a circuit breaker on the field supply to the terminal base is still required for wiring protection and code compliance.

Q: When a point faults and auto-resets, will it re-energize automatically if the output is still commanded on?

Yes. If the controller program has the output tag set to 1 when the fault clears, the output re-energizes immediately on auto-reset. For safety-critical outputs or any application where automatic restart after a fault is not acceptable, the program should monitor the diagnostic bit and require explicit operator or logic acknowledgment before re-enabling the output.

Q: Can sinking (NPN) field devices be connected to this module?

The 1734-OB8E is a sourcing output — it provides 24V to the load, with the load returning to 0V at the field supply negative. NPN/PNP refers to sensor output types, not load types. Any 24V DC load that draws current from a positive supply can be connected to a sourcing output correctly. If the question is about connecting NPN sensors as inputs, that requires a POINT I/O input module — not an output module.

1734-OB8E Ser C Point I/O Digital Source Output Module Genuine New 1734OB8E