Allen-Bradley 1756-OF8K – 8-Channel Analog Output Module (Current/Voltage) | ControlLogix Platform
Engineering Background: The 1756-OF8K is a high-density analog output module designed for the Allen-Bradley ControlLogix chassis. It delivers 8 independently configurable output channels supporting both current (4–20 mA) and voltage (±10 V / 0–10 V) signal types, making it a versatile solution for process control, motion coordination, and drive interfacing in demanding industrial environments.
Product Positioning: Targeted at process engineers and system integrators who require precise, multi-channel analog control within a ControlLogix 1756 backplane architecture. The 1756-OF8K is the preferred choice for applications demanding high channel density, fast update rates, and seamless Studio 5000 integration.
Complete Technical Specifications
- Catalog Number: 1756-OF8K
- Series: ControlLogix (1756)
- Manufacturer: Allen-Bradley / Rockwell Automation
- Output Channels: 8 (independently configurable)
- Output Signal Types: Current: 4–20 mA / Voltage: ±10 V, 0–10 V
- Resolution: 16-bit DAC
- Output Accuracy: ±0.1% of full scale (at 25°C)
- Update Rate: <1 ms per channel (direct connection)
- Backplane Current Draw: 125 mA @ 5 VDC; 3 mA @ 24 VDC
- Field-Side Power: External 24 VDC required
- Operating Temperature: 0°C to 60°C (32°F to 140°F)
- Storage Temperature: -40°C to 85°C
- Relative Humidity: 5–95% non-condensing
- Isolation: 250 VAC continuous (channel-to-backplane)
- Wiring: Removable terminal block (RTB), 1756-TBCH or 1756-TBS6H compatible
- Dimensions (H × W × D): 94.0 × 94.0 × 58.4 mm
- Weight: Approx. 0.5 kg
- Certifications: UL, CE, C-Tick, ATEX (Zone 2)
- Programming Software: Studio 5000 Logix Designer v21+
- Communication: ControlLogix backplane (1756 chassis)
Proven Application Environments
- Oil & gas process control (valve positioner, flow control loops)
- Chemical and pharmaceutical batch processing
- Variable frequency drive (VFD) speed reference signals
- Boiler and HVAC control systems
- Water/wastewater treatment plant automation
- Automotive assembly line motion coordination
- Food & beverage continuous process lines
Engineering Advantages
- High Channel Density: 8 outputs in a single 1756 slot — reduces chassis footprint and wiring cost.
- Dual Signal Mode: Each channel independently switchable between current and voltage output without hardware changes.
- 16-Bit Resolution: Provides 65,536 discrete output steps for ultra-precise process control.
- Fast Update Rate: Sub-millisecond channel update supports high-speed closed-loop control.
- Fault State Configuration: Configurable hold-last-state or go-to-safe-value on controller fault — critical for process safety.
- Ramp/Rate Limiting: Built-in output ramp control prevents actuator shock on setpoint changes.
- Hot-Swap Capable: Module can be replaced under power without shutting down the chassis.
System Architecture & Signal Flow
The 1756-OF8K resides in any slot of a 1756 ControlLogix chassis and communicates over the high-speed ControlLogix backplane. The Logix controller writes output data tags (O.Ch[n].Data) via the backplane at the configured RPI (Requested Packet Interval). The module’s internal 16-bit DAC converts digital values to analog field signals. Field wiring connects via a removable terminal block (RTB), allowing module replacement without disturbing field wiring. Each channel supports individual scaling, engineering unit conversion, and alarm limits configured in Studio 5000.
Typical Signal Flow: Studio 5000 Tag → Backplane RPI → 1756-OF8K DAC → RTB Terminal → Field Device (Valve / VFD / Transmitter)
Sourcing & Quality Verification
- Source: Authorized distributor stock and verified surplus channels
- Condition: New (factory-sealed) or Refurbished (tested to OEM spec)
- Testing Protocol: Full functional test on live 1756 chassis; all 8 channels verified at 4–20 mA and ±10 V
- Firmware: Latest compatible firmware pre-loaded where applicable
- Warranty: 12-month Konmask warranty covering manufacturing defects and functional failure
- Counterfeit Prevention: All units inspected for label authenticity, PCB markings, and serial number validation against Rockwell Automation records
- Packaging: Anti-static ESD bag + foam-lined carton for international shipping
Procurement Process
- Submit RFQ: Contact support@konmask.com with your required quantity, condition preference (new/refurbished), and delivery timeline.
- Quotation: Receive a formal quotation within 1 business day including unit price, lead time, and shipping options.
- Order Confirmation: Approve the quotation; Konmask issues a proforma invoice.
- Payment: T/T bank transfer, PayPal, or credit card accepted.
- Shipment: DHL / FedEx / UPS express with full tracking. Export documentation (commercial invoice, packing list, COO) provided.
- After-Sales: Technical support available via email or WhatsApp (+0086 19859288691) for installation and commissioning queries.
Technical FAQ
Q: Is the 1756-OF8K compatible with all ControlLogix chassis?
A: Yes. It is compatible with all 1756 series chassis (4, 7, 10, 13, 17-slot) and all ControlLogix controllers (L6x, L7x, L8x series).
Q: Can I mix current and voltage outputs on the same module?
A: Yes. Each of the 8 channels is independently configurable for current (4–20 mA) or voltage (±10 V / 0–10 V) output via Studio 5000 configuration — no hardware jumpers required.
Q: What happens to outputs if the controller faults?
A: Each channel can be individually configured to hold last state, ramp to a defined safe value, or go to zero — configurable in the module’s fault/program mode output settings in Studio 5000.
Q: What terminal block is required?
A: The 1756-OF8K uses a 36-pin RTB. Compatible blocks: 1756-TBCH (cage clamp) or 1756-TBS6H (spring clamp). RTBs are sold separately.
Q: Is a firmware update required after installation?
A: Firmware is managed automatically by the ControlLogix controller. Ensure your Studio 5000 project targets the correct module revision. Konmask pre-loads the latest compatible firmware on refurbished units.
Q: Do you provide a certificate of conformance (CoC)?
A: Yes. A CoC is available upon request for all new and refurbished units.
© 2026 Konmask.com. All rights reserved.
Original Source: https://Konmask.com
Contact: support@konmask.com | +0086 19859288691
