When Hydraulic Positioning Drifts, Production Stops
Hydraulic cylinders that lose repeatability mid-shift create scrap, slow cycle times, and unplanned downtime. The Allen-Bradley 1756-HYD02 solves that problem directly. It is a ControlLogix hydraulic servo module built to close a high-speed position loop between a linear displacement transducer (LDT) and a proportional or servo valve.
This module controls up to two hydraulic axes from a single slot. It reads LDT feedback, applies a PID servo loop with feed-forwards and directional scaling, and outputs a ±10V DC analog velocity command. The result is accurate, repeatable motion for demanding hydraulic applications.
Technical Specifications That Matter
Servo loop control. The 1756-HYD02 uses a proportional, integral, and differential (PID) loop with feed-forwards and directional scaling. Gain resolution is 32-bit floating point, which supports fine tuning across a wide range of hydraulic valve responses.
Position feedback range. The module handles an absolute position range of 230,000 LDT counts. Selectable loop rates run from 500 Hz to 4 kHz, letting you balance loop speed against hydraulic system dynamics.
I/O and outputs. LDT input accepts PWM with start/stop rising or falling edge. The registration input is optically isolated and current sinking. Analog output resolution is 16 bits. Discrete outputs are solid-state isolated relay contacts rated at 24VDC nominal.
Power and thermal. Backplane current draw is 700 milliamps at 5 Volts and 2.5 milliamps at 24 Volts. Power dissipation is 5.5 Watts. Isolation voltage is 30 Volts continuous, user-to-system.
Environmental range. Operating temperature is 0 to 60 degrees Celsius. Storage temperature is -40 to 85 degrees Celsius. Relative humidity is 5 to 95% non-condensing. Vibration meets IEC 60068-2-6 at 2g, 10-500 Hertz. Shock meets IEC 60068-2-27 at 30g operating and 50g non-operating.
Where the 1756-HYD02 Fits
Steel and metal forming. Hydraulic presses and forming lines need tight position control. The 230,000 LDT count range and 4 kHz selectable rate support fast, accurate ram positioning.
Oil and gas valve actuation. Hydraulic actuators on wellheads and pipeline systems benefit from the module’s isolated registration input and robust environmental ratings. The ±10V DC output drives proportional valves directly.
Heavy equipment test stands. Two-axis control in one slot simplifies cabinet layout. The 32-bit floating point gain resolution helps engineers tune force and position loops on the same chassis.
Installation and Integration
Install the 1756-HYD02 in any slot of a 1756 ControlLogix chassis. Slide it in until it clicks into place. Key the removable terminal block (RTB) to prevent connecting the wrong RTB to a module. Use a unique keying pattern for every slot. Both cage clamp and spring clamp RTBs are supported. Compatible terminal blocks are 1756-TBCH and 1756-TBS6H.
For fieldbus integration, note that wiring into networks such as EtherNet/IP may require an external gateway or connection module. Confirm cables and gateways with your supplier before commissioning.
Maintenance and Reliability
Inspect terminal connections and RTB seating periodically. Verify backplane current draw stays within the 700 milliamp at 5 Volts and 2.5 milliamp at 24 Volts limits. Keep cabinet temperature within the 0 to 60 degrees Celsius operating range. Follow the manufacturer’s safety manual for all service procedures.
Please verify current lifecycle status and availability with Oil AutoTech before ordering. Contact Oil AutoTech today for pricing and availability.
