Digital Electronics: Repeatable Control, Simple Operation, and Diagnostic Capabilities

Our field-proven electronics provide excellent position control in response to modulating control signals. This maximizes control loop performance by ensuring that the actuator responds exactly as the control loop requires.

The DCM-3 is equipped with a local interface panel for pushbutton calibration functions without the need for external devices or software. LED diagnostic lights display a number of status conditions.

The DCM-3 is also equipped with a HART® communications interface to provide bidirectional digital communications over the existing analog demand wiring—providing access to the added functions and information without interfering with control or requiring new wiring. Communications can be established either remotely or locally using any standard HART®-based communication tool and is compatible with common asset management systems. Optionally, the DCM can be equipped with Foundation Fieldbus® or Profibus PA® communication capability.

Beck’s Contactless Position Sensor (CPS) also resides within the actuator, and provides reliable internal position feedback to the DCM for position control. The DCM also uses the sensor signal to source a 4–20 mA external position signal for remote monitoring of actuator position. Unlike typical position sensors, the CPS does not wear due to its contactless design.

Over-travel Limit Switches

Beck actuators include heavy-duty, single-pole, double-throw (SPDT) switch mechanisms for electrical over-travel protection. Switch cams will not slip because each is mounted to the shaft by an integral, tangential clamping means—with no set screws to mar the shaft.

Every actuator is equipped with two over-travel limit switches. Optionally, actuators can be equipped with up to four auxiliary switches that can be set to operate at any desired point of actuator travel, thus providing discrete inputs for control or indication.

Common throughout most Beck actuator models, the SPDT switches provide the following:

• A maximum rating of 6 A at 120 V ac (three times the maximum motor current for most models) to ensure long life.
• Auxiliary switches are field-adjustable with infinite positioning throughout the actuator’s travel range.
• May initiate secondary functions or provide remote indication of actuator position.

Drive Train: Power and Durability

Beck’s durable gear train maintains accurate, consistent positioning even under the demanding conditions of an active control loop.

• Gear trains employ a unique, all spur gear construction using only heat-treated alloy steels and ductile iron.
• Efficient, wide-faced spur gears ensure long life and eliminate wear-induced backlash and positioning inaccuracies common in worm gear and “Scotch-yoke” designs.
• Integral self-locking mechanism ensures that actuators hold a minimum of 200% of rated torque with the motor de-energized.
• Durable design provides up to 4 days of protection against intermittent or extended accidental stalls.

Stall protection is provided by the DCM. If the motor tries to run in one direction for more than 300 seconds, the DCM will shut off power to the motor and a status indication LED will activate indicating a stall.

Local Manual Control

All Beck actuators are built with local positioning capabilities. An electric Handswitch allows electrical local operation of the actuator, while a convenient Handwheel, or Handcrank on some high torque actuators, allows manual positioning of the actuator output shaft without electric power.

Handswitch

The electric Handswitch allows the actuator to be positioned locally and is very useful for the initial setup of the actuator and linkage. It also serves as a diagnostic tool or a backup control device in the event the loop controller or demand signal malfunctions.

Handwheel

Even in the absence of power, and with full load applied, the actuator output shaft can be manually positioned using the easy-to-turn, spoke-free Handwheel. No clutch mechanism is required and mechanical stops protect against manual overtravel.

Housing: Superior Protection and Convenient Access to Components

Beck actuators feature a cast aluminum body with individual compartments to protect components from moisture and dirt, and allow easy access for installation and calibration.

• Precision-machined aluminum alloy castings with corrosion-resistant polyurethane paint provide a rugged, dust-tight, weatherproof Type 4X enclosure.
• Individual compartments protect all major components: Motor, DCM, CPS, gear train and installation wiring terminal board.
• Gasketed covers provide extra protection for abusive indoor environments and harsh outdoor climates.
• Each compartment can be accessed without exposing other components to the environment.
• Output and Handwheel shafts are sealed with weatherproof, double-lip cartridge seals.

Linkage: Beck Linkage Kits and Link-assist Program Ensure the Best Connection

The unique design of the crank arm allows infinite position adjustment to simplify installation. Engineered linkage kits are available to complete the connection from the crank arm to the damper. Once the connection is made, the linkage length may be adjusted, simplifying the final mechanical calibration. Also, Beck rod ends incorporate a bearing to compensate for some lateral misalignment.

Beck’s Link-assist program provides a printout showing the optimum actuator and linkage configuration for the application. The linkage arrangement can be characterized to match the torque profile of the application. Request this free service to save time, simplify installation and ensure the best performance at the lowest possible cost.