Quick start

Parameterization of the main settings

The module is factory-set such that in most applications it is operational without further parameterization.

Set the parameter Max Current [%] (0x8pp0:10) such that the maximum inductance current is not exceeded. If an EP8309 with 1.2 A rated current and an inductance with a maximum current of 600 mA is used, this parameter can be set to 50 (50%). This means that, at a maximum process data value of 32767dec a coil current of +600 mA is reached (not +1 A).

Info data objects

Via the info data objects additional information can be transferred synchronously. For each channel two of these objects are available.

The synchronous info data can be activated in the TwinCAT System Manager via the "Process Data" tab (0x1A07).

Quick start 1:
Info data objects - activation of the synchronous info data

Objects 0x8060:21 and 0x8060:22 can be used to set the value to be transferred synchronously.

Quick start 2:
Info data objects – selection of the value to be transmitted

The following entries are available:

Value

Text

Description

0

Actual current

Actual current in mA

1

Set current

Set current in mA

2

Duty Cycle

The PWM duty cycle of the output stage. A value of 1000 corresponds to 100% duty cycle.

Watchdog

The analog output value can, e.g. in the case of a failure of communication with the controller, be set to a user-specific value.

Quick start 3:
Watchdog

Three parameterization options are available for this purpose:

Watchdog object (0x8060:05)

Behavior

0: Default watchdog value

The substitute switching value (0x8060:0D) is output on error.

1: Watchdog ramp active

On error the output value is moved to the default value (0x8060:0D) with the ramp time set under 0x8060:0E

The ramp time is specified in digits / ms.

If the entry is 100 and the default value 0, for example, it takes 327 ms (32767/100) for the output value to change from the maximum value (32767) to the default value in the event of a fault.

2: Last output value active

In the event of a fault (watchdog drop) the last process data is issued.

Optimization of the current control parameters

In order to be able to support all possible loads ex factory, the terminal was parameterized with moderate controller characteristics. Current regulation can be improved significantly by adapting the controller parameters to the actual load.

To determine the settings a current pulse is applied to the load. This pulse can be picked up with an oscilloscope or with TwinCAT ScopeView.

For evaluation with TwinCAT ScopeView the set and actual current is displayed in the synchronous info data.

Quick start 4:
Selecting the synchronous info data

Quick start 5:

EP8309 standard parameters (20 ms/div)

Green: Set current
Red: Actual current

Quick start 6:

Optimized parameters (20 ms/div)

Green: Set current
Red: Actual current

The required step response can be set using the parameters Kp,Ki, and Kd (0x8060:12 to 0x8060:14).

Dithering

Dithering involves modulating a square wave signal on top of the actual output value. The modulated signal results in continuous movement of a valve piston, for example.
This reduces static friction and prevents sudden "breakaway" of the piston.

The configuration required for this depends a lot on the particular application.
To activate dithering, the object 0x8060:03 ("Enable dithering") and the corresponding control bit must be set.

Quick start 7:
Enable dithering

The following parameters can be set:

Value

Text

Description

0x8060:1E

Dithering frequency [Hz]

Frequency of the applied dither in Hz

0x8060:1F

Dithering amplitude [%]

Amplitude of the applied dither (in % of the rated terminal current)

The controller parameters themselves (Kp,Ki, and Kd) also play a role.
In the diagrams a dither of 10 % of the rated current is shown as 100 Hz.
The controller has 5 ms for compensating a current pulse of 10 %. The steepness of the current rise is limited by the controller parameters and the inductance.
The actual current should follow the set current. This is enabled through suitable settings of the controller and dither parameters (frequency and amplitude).

Quick start 8: EP8309 100 Hz dither with 10 % amplitude,
poor parameterization (5 ms/div)

Green: Set current
Red: Actual current

Quick start 9:

EP8309 100 Hz dither with 10 % amplitude,
better parameterization (5 ms/div)

Green: Set current
Red: Actual current