Allen-Bradley 1771-OVN Digital Output Module
The Allen-Bradley 1771-OVN, also cataloged as the 1771-OVN Digital Output Module, operates as a dedicated hardware component for low-side current sinking output control within Allen-Bradley PLC-5 systems. It drives up to 32 independent DC field loads across a 10 to 30 VDC operating voltage range, providing direct physical execution of control logic commands issued by the central rack processor.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1771-OVN |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 1.08 lbs (0.49 kg) |
| Dimensions | Standard 1771 Single-Slot I/O Module Form Factor |
| Operating Temp | 0 to 60 deg C |
| Power Consumption | Backplane current draw dependent on active points |
| Module Type | Digital Output Module (Low-True Sinking) |
| Output Count | 32 Outputs |
| Operating Voltage Range | 10 to 30 VDC |
| Logic Configuration | Low-True (Current Sinking) |
Backplane Bus Communication Velocity & I/O Density Scaling
The 1771-OVN maximizes I/O density scaling by supporting 32 discrete DC outputs in a single 1771 chassis slot. Its low-true (current sinking) architecture routes field current from connected field devices to the module common, enabling direct interfacing with sinking load configurations without sacrificing backplane bus communication velocity. Internal optical isolation separates the 32 high-density field output channels from the logic backplane, protecting internal processor circuits from field-side voltage spikes and electrical ground loops.
Frequently Asked Questions
Q: What does the "Low-True" designation mean for the 1771-OVN output circuits?
A: "Low-True" indicates a current sinking configuration where an active logic state turns on an internal switch that pulls the output channel to the negative DC return path, completing the load circuit to ground.
Q: Can the 1771-OVN module be inserted or removed while backplane power is applied?
A: No, backplane power to the 1771 chassis must be disconnected prior to inserting or removing the 1771-OVN module to prevent electrical damage or unexpected signal state changes.
Field Installation Guidelines
- Keying and Insertion: Insert the module keying bands into the chassis backplane connector corresponding to the 1771-OVN keying positions, then seat the module firmly into the slot.
- Field Termination Wiring: Connect field wiring to the compatible 1771 wiring arm, ensuring external 10-30 VDC power supplies and load ground returns are correctly assigned to the appropriate module terminals.
- Shielding and Grounding: Route DC output field wiring away from high-voltage AC lines to minimize inductive noise coupling into low-voltage DC sinking circuits.
Allen-Bradley 1771-OVN Digital Output Module
Allen-Bradley 1771-OVN Digital Output Module
The Allen-Bradley 1771-OVN, also cataloged as the 1771-OVN Digital Output Module, operates as a dedicated hardware component for low-side current sinking output control within Allen-Bradley PLC-5 systems. It drives up to 32 independent DC field loads across a 10 to 30 VDC operating voltage range, providing direct physical execution of control logic commands issued by the central rack processor.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1771-OVN |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 1.08 lbs (0.49 kg) |
| Dimensions | Standard 1771 Single-Slot I/O Module Form Factor |
| Operating Temp | 0 to 60 deg C |
| Power Consumption | Backplane current draw dependent on active points |
| Module Type | Digital Output Module (Low-True Sinking) |
| Output Count | 32 Outputs |
| Operating Voltage Range | 10 to 30 VDC |
| Logic Configuration | Low-True (Current Sinking) |
Backplane Bus Communication Velocity & I/O Density Scaling
The 1771-OVN maximizes I/O density scaling by supporting 32 discrete DC outputs in a single 1771 chassis slot. Its low-true (current sinking) architecture routes field current from connected field devices to the module common, enabling direct interfacing with sinking load configurations without sacrificing backplane bus communication velocity. Internal optical isolation separates the 32 high-density field output channels from the logic backplane, protecting internal processor circuits from field-side voltage spikes and electrical ground loops.
Frequently Asked Questions
Q: What does the "Low-True" designation mean for the 1771-OVN output circuits?
A: "Low-True" indicates a current sinking configuration where an active logic state turns on an internal switch that pulls the output channel to the negative DC return path, completing the load circuit to ground.
Q: Can the 1771-OVN module be inserted or removed while backplane power is applied?
A: No, backplane power to the 1771 chassis must be disconnected prior to inserting or removing the 1771-OVN module to prevent electrical damage or unexpected signal state changes.
Field Installation Guidelines
- Keying and Insertion: Insert the module keying bands into the chassis backplane connector corresponding to the 1771-OVN keying positions, then seat the module firmly into the slot.
- Field Termination Wiring: Connect field wiring to the compatible 1771 wiring arm, ensuring external 10-30 VDC power supplies and load ground returns are correctly assigned to the appropriate module terminals.
- Shielding and Grounding: Route DC output field wiring away from high-voltage AC lines to minimize inductive noise coupling into low-voltage DC sinking circuits.
