EPOS4 / IDX: Analog set value commanding

Topic:

How to configure an EPOS4 or an IDX to command the speed or current control by an analog set value?

Technical background:

An analog set value can be used to command the "CSV - Cyclic Synchronous Velocity" or "CST - Cyclic Synchronous torque" mode instead of commanding it by the bus interface. The target speed or target torque is internally calculated on the base of the voltage applied to one of the analog inputs and the configured analog input scaling.

Please refer to chapters "Analog input current set value properties" (Object: 0x3170) and "Analog input velocity set value properties" (Object: 0x3171) of EPOS4's resp. IDX's "Firmware Specification" to learn more about the details of the related objects and their configuration as well as processing of the data.

Preconditions:

• It is mandatory that there is at least EPOS Studio V3.6 installed.
  The "EPOS Studio" version can be checked by its title bar or by the menu item "Help -> About EPOS Studio"
  
  
• It is mandatory that there is at least the EPOS4 / IDX firmware 0x160 installed.
  The firmware version can be checked by right-clicking on the EPOS4 resp. IDX of the Workspace or Communication tree and selecting "Properties" by the pop-up menu and clicking the "Version" tab of the dialog box.
  

Solution:

Method 1:
Configuration by EPOS Studio's "Startup" wizard

The most simple way to configure "Commanding by an Analog set value" is to use the "Startup" wizard's "Analog Input" configuration section. All required configuration can be processed by this, e.g. ...

• ... the control function assigned to an analog input.
• ... the scaling of the analog set value.
• ... the activation of the required operating mode for the set value.

Examples of different "Analog 1 - Set value current" configuration:

Examples of different "Analog 2 - Set value velocity" configuration:

Remarks:

• The two configured "Voltage / Current" resp. "Voltage / Velocity" limits define the set value gradient.
• The configured "Velocity" resp. "Current" values of both scaling points will be the maximum values in use even if the voltage level applied to the analog input exceeds the configured value.
• The "Activate Cyclic Synchronous ..." checkbox has to be marked to ensure that the required operating mode ("CSV" or "CST") is automatically activated.
• The "Startup" wizard has to be closed by the "Finish" button to finally save the configuration in the EPOS4 resp. IDX.

Method 2:
Configuration by EPOS Studio's Object Dictionary or a master (PLC, PC, ...)

• Please refer to the EPOS4's resp. IDX's "Firmware specification" to find detailed information about the objects mentioned by the following quick hints.
• The analog input functionality has to be assigned by the object 0x3161 "Analog input n configuration".
• The scaling of the analog input signal has to be configured by the object 0x3170 "Analog input current set value properties" resp. object 0x3171 "Analog input velocity set value properties".
• The operating mode ("CSV" or "CST") has to be configured by object 0x6060 "Modes of operation".
  • In case of analog set value commanding for speed control the "Cyclic Synchronous Velocity Mode (CSV)" (i.e. 0x6060 = 9) has to be configured.
  • In case of analog set value commanding for current / torque control the "Cyclic Synchronous Torque Mode (CST)" (i.e. 0x6060 = 10 = 0x0A) has to be configured.
• After all configuration has been processed, all parameters have to be saved persistently by the object 0x1010 "Store parameters". Otherwise all configuration is lost after a reset or power down of the EPOS4 resp. IDX.
• Process data feedback:
  • The analog input voltages can be read by object 0x3160 "Analog input n voltage".
  • The internally calculated current resp. torque command of the analog commanded "CST" mode can be read by the object 0x30D0 "Current demand value" resp. object 0x6071 "Target torque".
  • The internally calculated velocity command of the analog commanded "CSV" mode can be read by the object 0x60FF "Target velocity".

Restrictions:

• It is only possible to command the EPOS4 resp. IDX in speed or current / torque control mode by an analog set value.
  => It is not(!) possible to command the target position or the target speed value of any position control operating ("PPM", "CSP") mode by analog signals.
  
  
• The voltage level present at the analog input is captured at a rate of 2.5 kHz (= every 400 µs = 0.4 ms) and used for commanding the velocity or current / torque control depending on the configured mode.
  • The 2.5 kHz analog's input capture rate corresponds to the velocity control rate in use by EPOS's operating mode CSV (= "Cyclic Synchronous Velocity"). This means that updated analog set values are captured and processed within each velocity control cycle.
  • The current resp. torque control rate of the EPOS4 is 25 kHz (= every 40 µs), i.e. 10 times faster than the set value signal capturing of the analog inputs. Therefore it is not possible to command the current / torque control of the EPOS4 operating mode CST (= "Cyclic Synchronous Torque") by analog set values with the extremely dynamic control rate of 25 kHz. Updated analog set values will just be captured every 400 µs and forwarded to the current / torque control then.

Cross Reference:

• EPOS4: Connecting a potentiometer to an analog input