The Maxon EPOS3 is motor controller for brushed and brushless motors. It behaves as an etherCAT slave. Aim of this manual is to set op the EPOS3 module to work with matlab xPC. For a general introduction on how to set up xPC and EtherCAT please refer to this website. This manual does not replace the official documents provided by Maxon. It is the users own task to ensure save operation of the device. We do not take any responsibility for injuries or damage caused by the use of this manual.

Before opening the configurator, you need to make sure the ESI file describing the IO adresses, is in the appropriate location on the harddrive. The newest version of this file can be found on the maxon webpage. Copy it to <configurator program directory>/EtherCAT and restart/open the configurator. Emperical testing has shown that the configurator only works properly on 32-bit systems.

After you scanned for the device, you might run into some error mesages. Ignore them and click Reload I/O Devices and make sure the device comes into operation mode (Ethercat status LED is solid green). This can be checked by clicking on the "Drive 1 (EPOS3) device in the I/O tree and looking at the current state in the Online tab. Next, we will setup the device configuration in de following steps:


  1. In the Slots tab, remove the current Module by selecting it in the left plane and clicking the X in the center. Now, select the desired mode (e.g. CSP, PP...) in in the right plane and click the arrow (smaller than sign) in the center. Note that you can skip this step if the left plane allready displayes the wright mode.
  2. If you want certain properties -- like torque constants, encoder resolution etc -- to be set each time you run a model, a startup sequence can be defined through the Startup tab.
  3. Add additional tasks to the system. The number of cycle ticks for the task should be 1.

Motor specific settings

The following settings depend on the motor connected to the EPOS3 module. The settings can be added in the startup tab in the EtherCAT confiurator. The values between brackets are for the Maxon EC-4pole 22 120W 24V with Scancon SGH24 2000.

  • 0x6402:00 (10) Motor type
  • 0x6410:01 (481) Nominal current
  • 0x6410:02 (1300) Output current limit
  • 0x6410:03 (2) Pole pair number
  • 0x6410:04 (12500) Maximal motor speed
  • 0x6410:05 (67) Thermal time constant windings
  • 0x6410:06 (13500) Motor torque constant
  • 0x2210:01 (2000) pulse number
  • 0x2210:02 (1) position sensor type
  • 0x2210:04 (0 or1, depends on your application) polairity

note: Double click the value to be set to edit the settings in different formats (decimal, hex, etc.). Units are not SI units see the Maxon manual for the units

Simulink/xPC settings

The EPOS3 controllers require the use of distributed clocks. This can be set in the parameters of the EtherCAT Init block via the enable DC checkbox.