A-B 1746-QS Synchronized Axes Control Module benefits

Why Use This System?

Because you can interact quickly and easily with the module’s control of

axis motion via the Hydraulic Configurator, this control system has

these benefits:

• faster setup and tuning of axes – the Hydraulic Configurator lets you

quickly set up and tune each axis independent of your ladder program.

• reduced cycle time – you can increase axis speed for faster operation

• smoother operation for longer machine life – you can profile accelerations

and decelerations of the hydraulic actuator to limit pressure spikes

• faster change-over to new parts – you can store setups (configuration

parameters) for quick an accurate change-over between parts

How Does It Work?

Monitoring Axis Position

The module has four LDT inputs. You configure each axis for an LDT

with a Pulse Width Modulated output (DPM) or a Start/Stop output

(RPM) by changing axis configuration parameters.

Controlling Axis Output

The module is a targeting controller: every two milliseconds its microprocessor

updates TARGET POSITION and target SPEED values. For

point-to-point moves, TARGET POSITIONS are generated so that

resulting speed, accelerations, and decelerations follow either a

trapezoidal or s-curve profile.

The MODE, ACCELERATION, DECELERATION, SPEED, and

COMMAND VALUE (requested position) are used to generate the

profile. You send these command words to the module through the

processor’s output image table. You may change them “on-the-fly“

while the axis is moving.

The module compares ACTUAL POSITION with TARGET POSITION to

determine position error. Every update, it uses the position error to adjust

drive output. PID gains are adjustable and can be applied selectively.

The module also provides two different feedforward algorithms;

EXTEND/RETRACT FEEDFORWARD, and EXTEND/RETRACT

ACCELERATION FEEDFORWARD. These feedforward terms provide

additional drive output to help the axis follow the target, freeing the

PID loop to correct for system nonlinearity and changes in load.