The Allen-Bradley 1734-OB8S is a safety-rated digital output module from the POINT Guard I/O family, certified to SIL 2 (IEC 61508) and PL d (ISO 13849-1). It provides 8 independent isolated safety sourcing outputs, each rated for 2.0A continuous at 24V DC with a peak current of 3.0A for 100 ms. With channel-to-channel isolation at 500V AC, the module ensures that a fault on one output does not propagate to others. Per-channel green status LEDs provide diagnostic visibility. Compatible with GuardLogix and Compact GuardLogix controllers, the 1734-OB8S is deployed in safety-critical actuator control: emergency stop relays, safety contactors, safety valves, motor brakes, and interlock-controlled power disconnects in automotive, process, and heavy machinery applications.
Frequently Asked Questions
Q: What is the difference between 1734-OB8 and 1734-OB8S?
A: The 1734-OB8S is a safety-rated output module (SIL 2 / PL d) with 2A per channel, while the 1734-OB8 is a standard output module rated at 0.5A per channel.
Q: What safety controllers work with the 1734-OB8S?
A: GuardLogix and Compact GuardLogix safety controllers. It is NOT compatible with standard (non-safety) ControlLogix.
Q: Are the output channels isolated from each other?
A: Yes, each of the 8 channels is independently isolated at 500V AC (channel-to-channel and channel-to-backplane).
Q: What is the peak current capability?
A: Each channel can deliver up to 3.0A for 100 ms — useful for inrush currents on safety contactors.
Q: What kind of loads can it drive?
A: Primarily safety contactors, safety relays, solenoid valves, and motor brakes. Inductive loads require external suppression.
Q: Does it include a terminal block?
A: Yes, a removable screw terminal block is included with the module.
Q: What is the minimum operating temperature?
A: 0°C (horizontal) or 0°C (vertical). Note this is narrower than standard POINT I/O modules due to the higher current rating.
