Relay Output Module | Allen-Bradley 1771-OW PLC-5
The 1771-OW is an 8-channel selectable relay output module designed for integration into Allen-Bradley 1771 I/O chassis driven by PLC-5 control systems. Arranged into four isolated groups of two channels each with individual commons, it provides versatile contact switching for resistive loads across 24 to 138 VAC RMS and 24 to 125 VDC voltage ranges. Each channel defaults to Normally Open (N.O.) operation but can be individually reconfigured via jumpers to Normally Closed (N.C.) logic to align with specific field control requirements.
Isolated Contact Control and Switching Performance
The 1771-OW provides optical and electrical isolation between backplane logic circuitry and field-side contacts, enabling all eight output relays to operate simultaneously under distinct load conditions. Optimized primarily for resistive loads, each contact supports a switching frequency up to 10 Hz with an operate/release time of 5 ms and a 1 ms bounce time. Off-state signal delay reaches 45 ms (±15 ms) on AC circuits and 50 ms on DC circuits.
Electrical Constraints and Backplane Powering
Operating directly from the backplane supply, the 1771-OW draws up to 700 mA at 5 VDC to energize internal relay coils. Continuous contact currents are rated up to 1.0 A per channel, with specific rating thresholds of 1.0 A at 30 VAC/VDC (30 W) and 0.25 A at 120 VAC/VDC. A minimum contact load of 10 mA at 24 V (AC or DC) is required to ensure reliable switching. Total module power dissipation ranges between 3.3 and 3.7 W, generating 11.3 to 12.7 BTU/hr of thermal dissipation.
Chassis Installation and Field Wiring
The module mounts into any standard slot of a 1771 I/O chassis except the leftmost processor/adapter slot. Physical slot keying uses plastic bands inserted between pins 6 and 8, and pins 16 and 18. Field wiring connects via a 1771-WD field wiring arm, supporting stranded conductors up to 14 AWG (maximum insulation thickness 3/64 in) with terminal screw torque specified at 7 to 9 in-lb. Signal wiring runs should not exceed 1,000 ft (304.8 m).
| Parameter | Specification |
|---|---|
| Model | 1771-OW |
| Brand | Allen-Bradley |
| Product Type | Selectable Relay Output Module |
| System Compatibility | PLC-5 Systems (1771 I/O Chassis) |
| Number of Channels | 8 outputs (4 isolated groups of 2 channels) |
| Contact Form | Selectable Normally Open (N.O.) / Normally Closed (N.C.) |
| Default Contact Configuration | Normally Open (N.O.) |
| AC Operating Voltage Range | 24–138 VAC RMS (resistive loads) |
| DC Operating Voltage Range | 24–125 VDC |
| Output Current Rating per Channel | 1.0 A max continuous (0.25 A @ 120 VAC/DC; 1.0 A @ 30 VAC/DC) |
| Minimum Contact Load | 10 mA @ 24 V (AC or DC) |
| Backplane Current Draw | 700 mA |
| Power Dissipation | 3.3–3.7 W |
| Thermal Dissipation | 11.3–12.7 BTU/hr |
| Switching Frequency | 10 Hz max |
| Operate / Release Time | 5 ms |
| Contact Bounce Time | 1 ms |
| Signal Delay (Off) | AC: 45 ±15 ms; DC: 50 ms |
| Wiring Arm Model | 1771-WD |
| Field Wiring Wire Gauge | 14 AWG max stranded |
| Wiring Arm Screw Torque | 7–9 in-lb (0.8–1.0 N·m) |
| Max Interconnect Cable Length | 1,000 ft (304.8 m) |
| Chassis Slot Keying Position | Between pins 6 & 8, and between pins 16 & 18 |
| Operating Temperature | 0 to 60 deg C |
| Storage Temperature | -40 to 85 deg C |
| Operating Relative Humidity | 5–95% (non-condensing) |
| Weight | 2.44 lbs (1.11 kg) |
Frequently Asked Questions
Q: How do you change the relay outputs on the 1771-OW between Normally Open and Normally Closed? A: Contact logic for each of the eight output channels is selected using internal jumpers on the module, which come factory set to Normally Open (N.O.) and can be repositioned individually to Normally Closed (N.C.).
Q: Which field wiring arm is required to connect field wiring to the 1771-OW? A: The 1771-OW uses the 1771-WD field wiring arm, which supports up to 14 AWG stranded wire tightened to 7–9 in-lb of screw torque.
Q: What are the current rating limits per output channel on the 1771-OW? A: Each output channel carries a maximum continuous current of 1.0 A at 30 VAC/VDC (30 W max) and 0.25 A when operating at 120 VAC/VDC.
Relay Output Module | Allen-Bradley 1771-OW PLC-5
Relay Output Module | Allen-Bradley 1771-OW PLC-5
The 1771-OW is an 8-channel selectable relay output module designed for integration into Allen-Bradley 1771 I/O chassis driven by PLC-5 control systems. Arranged into four isolated groups of two channels each with individual commons, it provides versatile contact switching for resistive loads across 24 to 138 VAC RMS and 24 to 125 VDC voltage ranges. Each channel defaults to Normally Open (N.O.) operation but can be individually reconfigured via jumpers to Normally Closed (N.C.) logic to align with specific field control requirements.
Isolated Contact Control and Switching Performance
The 1771-OW provides optical and electrical isolation between backplane logic circuitry and field-side contacts, enabling all eight output relays to operate simultaneously under distinct load conditions. Optimized primarily for resistive loads, each contact supports a switching frequency up to 10 Hz with an operate/release time of 5 ms and a 1 ms bounce time. Off-state signal delay reaches 45 ms (±15 ms) on AC circuits and 50 ms on DC circuits.
Electrical Constraints and Backplane Powering
Operating directly from the backplane supply, the 1771-OW draws up to 700 mA at 5 VDC to energize internal relay coils. Continuous contact currents are rated up to 1.0 A per channel, with specific rating thresholds of 1.0 A at 30 VAC/VDC (30 W) and 0.25 A at 120 VAC/VDC. A minimum contact load of 10 mA at 24 V (AC or DC) is required to ensure reliable switching. Total module power dissipation ranges between 3.3 and 3.7 W, generating 11.3 to 12.7 BTU/hr of thermal dissipation.
Chassis Installation and Field Wiring
The module mounts into any standard slot of a 1771 I/O chassis except the leftmost processor/adapter slot. Physical slot keying uses plastic bands inserted between pins 6 and 8, and pins 16 and 18. Field wiring connects via a 1771-WD field wiring arm, supporting stranded conductors up to 14 AWG (maximum insulation thickness 3/64 in) with terminal screw torque specified at 7 to 9 in-lb. Signal wiring runs should not exceed 1,000 ft (304.8 m).
| Parameter | Specification |
|---|---|
| Model | 1771-OW |
| Brand | Allen-Bradley |
| Product Type | Selectable Relay Output Module |
| System Compatibility | PLC-5 Systems (1771 I/O Chassis) |
| Number of Channels | 8 outputs (4 isolated groups of 2 channels) |
| Contact Form | Selectable Normally Open (N.O.) / Normally Closed (N.C.) |
| Default Contact Configuration | Normally Open (N.O.) |
| AC Operating Voltage Range | 24–138 VAC RMS (resistive loads) |
| DC Operating Voltage Range | 24–125 VDC |
| Output Current Rating per Channel | 1.0 A max continuous (0.25 A @ 120 VAC/DC; 1.0 A @ 30 VAC/DC) |
| Minimum Contact Load | 10 mA @ 24 V (AC or DC) |
| Backplane Current Draw | 700 mA |
| Power Dissipation | 3.3–3.7 W |
| Thermal Dissipation | 11.3–12.7 BTU/hr |
| Switching Frequency | 10 Hz max |
| Operate / Release Time | 5 ms |
| Contact Bounce Time | 1 ms |
| Signal Delay (Off) | AC: 45 ±15 ms; DC: 50 ms |
| Wiring Arm Model | 1771-WD |
| Field Wiring Wire Gauge | 14 AWG max stranded |
| Wiring Arm Screw Torque | 7–9 in-lb (0.8–1.0 N·m) |
| Max Interconnect Cable Length | 1,000 ft (304.8 m) |
| Chassis Slot Keying Position | Between pins 6 & 8, and between pins 16 & 18 |
| Operating Temperature | 0 to 60 deg C |
| Storage Temperature | -40 to 85 deg C |
| Operating Relative Humidity | 5–95% (non-condensing) |
| Weight | 2.44 lbs (1.11 kg) |
Frequently Asked Questions
Q: How do you change the relay outputs on the 1771-OW between Normally Open and Normally Closed? A: Contact logic for each of the eight output channels is selected using internal jumpers on the module, which come factory set to Normally Open (N.O.) and can be repositioned individually to Normally Closed (N.C.).
Q: Which field wiring arm is required to connect field wiring to the 1771-OW? A: The 1771-OW uses the 1771-WD field wiring arm, which supports up to 14 AWG stranded wire tightened to 7–9 in-lb of screw torque.
Q: What are the current rating limits per output channel on the 1771-OW? A: Each output channel carries a maximum continuous current of 1.0 A at 30 VAC/VDC (30 W max) and 0.25 A when operating at 120 VAC/VDC.
