linuxcnc-ethercat

RTelligent ECR and ECT Stepper Drivers

The lcec_rtec driver supports a number of RTelligent EtherCAT stepper drives, including the ECT60 and ECR60.

Setup

In your XML file, you should have an entry somewhat like this:

<masters>
  <master idx="0" appTimePeriod="2000000" refClockSyncCycles="1000">
    ...
    <slave idx="1" type="ECT60" name="x-axis">
      <modParam name="peakCurrent_amps" value="1.0"/>
      <modParam name="controlMode" value="closedloop"/>
      <modParam name="homeOffset" value="1"/>
    </slave>
	...
  </master>
</masters>

See the CiA 402 documentation for additional details about how to configure CiA 402 devices in LinuxCNC. At a minimum, you will need to include the cia402 HAL component.

Devices

This driver supports all known (as of early 2024) RTelligent EC-series EtherCAT stepper drives, including:

• ECR60 (one-axis 6A open-loop driver)
• ECR60x2 (two-axis 6A open-loop driver)
• ECR86 (one-axis 7A open-loop driver)
• ECT60 (one-axis 6A closed-loop driver)
• ECT60x2 (two-axis 6A closed-loop driver)
• ECT86 (one-axis 7A closed-loop driver)

Only the ECT60, ECR60x2, and ECT60x2 have been tested.

Caveats

My ECR60x2 (technically an EXR60X2A) has a few EtherCAT shortcomings that moderately impact its utility. First, ethercat sdos doesn’t show anything for the device. This makes is somewhat tricky to develop against, but shouldn’t impact its use. More annoyingly, it maps PDOs at 0x16n0 and 0x1An0 instead of 0x160n and 0x1A0n, so a bit of special configuration is needed to get the second axis to work. Finally, it only appears to support 2 TX PDOs, which means that we’ve had to disable some optional features to save PDO space.

From the docs, it appears that in closed-loop mode, EC* drivers measure distances in terms of encoder steps (usually 4000x per revolution), and in open-loop mode they measure in terms of motorResolution_pulses (usually 10000x per revolution). There does not appear to be a way to change these at the drive level, so scaling will need to be applied at some point in LinuxCNC to get reasonable distance units.

Configuration

This driver takes a number of <modParam> options that control its operation. There are a number of rtec-specific parameters, plus a number of additional cia402 modParams.

The parameters are listed in their single-axis form; dual-axis devices like the ECR60X2 and ECT60X2 have two sets of these parameters, one starting with ch1 and one starting with ch2. For example, ch1peakCurrent_amps and ch2peakCurrent_amps.

<modParam name="peakCurrent_amps" value="3.0"/&gt

Set the maximum current for the motor, in amps.

<modParam name="motorResolution_pulses" value="10000"/&gt

Set the number of pulses for a full motor rotation.

<modParam name="standbyTime_ms" value="500"/&gt

Set the standby time, before the drive drops down to standby current. See below.

<modParam name="standbyCurrent_pct" value="50"/&gt

Set the percentage of current used when in standby mode.

<modParam name="output1Func" value="general|alarm|brake|in-place"/&gt

Set the function for output port 1. See below for options.

<modParam name="output2Func" value="general|alarm|brake|in-place"/&gt

Set the function for output port 2. See below for options.

<modParam name="output1Polarity" value="nc|no"/&gt

Set the polarity for output port 1, either nc for normally-closed or no for normally open.

<modParam name="output2Polarity" value="nc|no"/&gt

Set the polarity for output port 2, either nc for normally-closed or no for normally open.

<modParam name="input3Func" value="general|..."/&gt

Set the function for input port 3. See below for options.

<modParam name="input4Func" value="general|..."/&gt

Set the function for input port 4. See below for options.

<modParam name="input5Func" value="general|..."/&gt

Set the function for input port 5. See below for options.

<modParam name="input6Func" value="general|..."/&gt

Set the function for input port 6. See below for options.

<modParam name="input3Polarity" value="nc|no"/&gt

Set the polarity for input port 3, either nc for normally-closed or no for normally open.

<modParam name="input4Polarity" value="nc|no/&gt

Set the polarity for input port 4, either nc for normally-closed or no for normally open.

<modParam name="input5Polarity" value="nc|no/&gt

Set the polarity for input port 5, either nc for normally-closed or no for normally open.

<modParam name="input6Polarity" value="nc|no/&gt

Set the polarity for input port 6, either nc for normally-closed or no for normally open.

<modParam name="filterTime_us" value="6400"/&gt

Set the filter time in microseconds.

<modParam name="shaftLockTime_us" value="1000"/&gt

Set the shaft lock time in microseconds.

<modParam name="motorAutoTune" value="true|false"/&gt

Enable or disable motor autotuning.

<modParam name="stepperPhases" value="2"/&gt

Set the number of stepper phases for the motor.

<modParam name="controlMode" value="openloop|closedloop|foc"/&gt

Set the control mode for the motor.

<modParam name="encoderResolution" value="4000"/&gt

The number of encoder pulses per revolution.

<modParam name="positionErrorLimit" value="4000"/&gt

Inputs

The single-axis ECR/ECT devices have 6 inputs. Inputs 1 and 2 are used for the encoder (and don’t appear to be available on the open-loop ECR models), while inputs 3, 4, 5, and 6 are available for use.

The inputXFunc (where X is 3, 4, 5, or 6) modParam controls the function of each input. The available options are:

general

The input is available to be used as a general-purpose input. Use this if you want LinuxCNC to take actions based on the state of the input rather than having the stepper drive itself take action.

cw-limit

The input is used for the clockwise limit/homing sensor, and is automatically used as part of CiA 402 homing mode.

ccw-limit

The input is used for the counter-clockwise limit/homing sensor, and is automatically used as part of CiA 402 homing mode.

home

The input is used for the home sensor, and is presumably used as part of CiA 402 homing mode.

clear-fault

The input is used to clear faults.

emergency-stop

The input is used as an emergency stop.

motor-offline

The input is used to take the motor offline.

probe1

The input is connected to probe #1.

probe2

The input is connected to probe #2.

</dl> On my ECT60, the pins come pre-assigned with various functions: - input 3 is `cw-limit` - input 4 is `ccw-limit` - input 5 is `home` - input 6 is `motor-offline` If you want to use these as general-purpose inputs, then you'll want to add `` to your XML config. On my system, all of the inputs default to "normally-closed" operation. You may also want to change this via ``. ## Outputs The single-axis ECR/ECT devices have 2 outputs. The `output1Func` and `output2Func` modParams control the function of each output. The available options are:

general

This output is a general-purpose output, available to LinuxCNC.

alarm

This output is triggered automatically when the drive triggers an alarm.

brake

This output is triggered automatically when the drive wishes to engage the brake.

in-place

This output is triggered automatically when the motor has reached its target position.

On my ECT60, the pins come pre-assigned as: - output 1 is `alarm` - output 2 is `brake` To use these as general-purpose outputs, you'll probably want to add ``. Like the input pins, you can also change the polarity between normally-open and normally-closed using ``. My ECT60 defaults to `nc` on both ports.

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