Allen-Bradley 1771-OZL Digital Contact Output Module
The Allen-Bradley 1771-OZL is a PLC-5 dry-reed relay contact output module engineered for low-power discrete switching applications. Featuring 8 Form A normally open (N.O.) outputs arranged in four isolated groups of two, it provides galvanic isolation between plant output devices and system logic backplane circuitry. It operates across 0 to 24 V AC/DC control ranges and integrates status LEDs on the front panel to indicate relay energization.
Isolated Reed Relay Architecture and Contact Load Limits
The 1771-OZL module utilizes hermetically sealed dry-reed contacts designed for low-voltage signal switching. The eight channels are divided into four pairs, with each pair sharing a distinct common terminal. This configuration supports an isolation voltage rating of 1000 V for open contacts and 1500 V between coil and contact lines.
Each contact output carries a continuous current limit of 100 mA with a power limit of 2.4 W resistive load for both DC and suppressed AC lines. A minimum contact load of 10 mA at 24 V AC/DC is required for reliable contact closure, while internal signal transition delays remain at 1 ms for both turn-on and turn-off operations.
Chassis Installation and Wiring Options
Designed for installation in a 1771 Series A or B I/O chassis, the 1771-OZL connects directly to the system backplane, drawing a maximum logic current of 420 mA at 5 VDC. Field connections attach via an interchangeable field wiring arm (such as the 12-terminal 1771-WD or 21-terminal 1771-WH), permitting module replacement without removing individual field wires.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | 1771-OZL |
| Brand | Allen-Bradley |
| Module Type | Digital Contact Output Module |
| Output Count | 8 Form A (Normally Open), 4 isolated sets of 2 |
| Operating Voltage Range | 0 to 24 VAC / 0 to 24 VDC |
| Maximum Output Current | 100 mA per output |
| Minimum Contact Load | 10 mA at 24 VAC / 24 VDC |
| Maximum Power Rating | 2.4 W resistive per output |
| Isolation Voltage | 1000 V (open contacts), 1500 V (coil-to-contact) |
| Signal Delay Time | 1 ms (ON and OFF) |
| Max Switching Frequency | 10 Hz |
| Backplane Current | 420 mA at 5 VDC |
| Power Dissipation | 2.0 W to 2.2 W |
| Thermal Dissipation | 6.9 BTU/hr to 7.6 BTU/hr |
| Compatible Wiring Arm | 1771-WD / 1771-WH |
| Weight | 1.00 lbs (0.45 kg) |
Frequently Asked Questions
Q: Does the 1771-OZL require external power supplies for logic operation?
A: No. Logic power is drawn directly from the 1771 chassis backplane at 420 mA. External power supplies are only required to power the switched output load devices within the 0 to 24 V limit.
Q: What field wiring arm model should be paired with the 1771-OZL?
A: The module is compatible with 1771-WD or 1771-WH field wiring arms, allowing field conductors to remain connected during module swaps.
Allen-Bradley 1771-OZL Digital Contact Output Module
Allen-Bradley 1771-OZL Digital Contact Output Module
The Allen-Bradley 1771-OZL is a PLC-5 dry-reed relay contact output module engineered for low-power discrete switching applications. Featuring 8 Form A normally open (N.O.) outputs arranged in four isolated groups of two, it provides galvanic isolation between plant output devices and system logic backplane circuitry. It operates across 0 to 24 V AC/DC control ranges and integrates status LEDs on the front panel to indicate relay energization.
Isolated Reed Relay Architecture and Contact Load Limits
The 1771-OZL module utilizes hermetically sealed dry-reed contacts designed for low-voltage signal switching. The eight channels are divided into four pairs, with each pair sharing a distinct common terminal. This configuration supports an isolation voltage rating of 1000 V for open contacts and 1500 V between coil and contact lines.
Each contact output carries a continuous current limit of 100 mA with a power limit of 2.4 W resistive load for both DC and suppressed AC lines. A minimum contact load of 10 mA at 24 V AC/DC is required for reliable contact closure, while internal signal transition delays remain at 1 ms for both turn-on and turn-off operations.
Chassis Installation and Wiring Options
Designed for installation in a 1771 Series A or B I/O chassis, the 1771-OZL connects directly to the system backplane, drawing a maximum logic current of 420 mA at 5 VDC. Field connections attach via an interchangeable field wiring arm (such as the 12-terminal 1771-WD or 21-terminal 1771-WH), permitting module replacement without removing individual field wires.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | 1771-OZL |
| Brand | Allen-Bradley |
| Module Type | Digital Contact Output Module |
| Output Count | 8 Form A (Normally Open), 4 isolated sets of 2 |
| Operating Voltage Range | 0 to 24 VAC / 0 to 24 VDC |
| Maximum Output Current | 100 mA per output |
| Minimum Contact Load | 10 mA at 24 VAC / 24 VDC |
| Maximum Power Rating | 2.4 W resistive per output |
| Isolation Voltage | 1000 V (open contacts), 1500 V (coil-to-contact) |
| Signal Delay Time | 1 ms (ON and OFF) |
| Max Switching Frequency | 10 Hz |
| Backplane Current | 420 mA at 5 VDC |
| Power Dissipation | 2.0 W to 2.2 W |
| Thermal Dissipation | 6.9 BTU/hr to 7.6 BTU/hr |
| Compatible Wiring Arm | 1771-WD / 1771-WH |
| Weight | 1.00 lbs (0.45 kg) |
Frequently Asked Questions
Q: Does the 1771-OZL require external power supplies for logic operation?
A: No. Logic power is drawn directly from the 1771 chassis backplane at 420 mA. External power supplies are only required to power the switched output load devices within the 0 to 24 V limit.
Q: What field wiring arm model should be paired with the 1771-OZL?
A: The module is compatible with 1771-WD or 1771-WH field wiring arms, allowing field conductors to remain connected during module swaps.
