[etherlab-users] Beckhoff EL7031

Tue Apr 18 00:46:40 CEST 2017

Hi,

We don't use Simulink, so unfortunately I won't be much help there.  As I said below, on the EL7031 you need to "Every cycle, set the motors TargetPosition (7010:11), even if its stationary."  Here is a link to a post which talks about creating a motion profile for a simple move (and a bunch of other things).
http://lists.etherlab.org/pipermail/etherlab-users/2016/002906.html

That is of course a very simple example and doesn't even consider acceleration.  You can dynamically calculate simple motion profiles based on the kinematic equations (i.e. http://www.physicsclassroom.com/class/1DKin/Lesson-6/Kinematic-Equations).  But you will also most likely want to apply smoothing to the motion profiles and coordinate multiple axes together.

With some quick googling (simulink motion profile) here are some links that may help get started for Simulink, though most of what I've found seems to only deal with point to point moves:
https://au.mathworks.com/matlabcentral/fileexchange/16352-advanced-setpoints-for-motion-systems?requestedDomain=www.mathworks.com
http://www.dct.tue.nl/New/Lambrechts/Advanced_Setpoints.pdf
http://mme.uwaterloo.ca/~mte360/files/Matlab%20Simulink%20Tutorial.pdf

Regards,
Grame.

-----Original Message-----
From: Ewan Houston [mailto:e.houston.1 at research.gla.ac.uk] 
Sent: Tuesday, 18 April 2017 2:08 a.m.
To: Graeme Foot <Graeme.Foot at touchcut.com>
Cc: etherlab-users at etherlab.org
Subject: Re: Beckhoff EL7031

Hi Graeme,

I am currently building a Simulink model to operate the hardware.

>From your previous description of how to control the EL7031 I see that I have to program my PDOs and SDOs into my m file for the EL7031. I think that is mostly fine. How do I calculate and implement the motion profile from there? I know how to add PDOs and SDOs to the m file but am lost after that. 

Cheers,

Ally.

On 10 Oct 2016, at 23:31, Graeme Foot <Graeme.Foot at touchcut.com> wrote:

> Hi,
> 
> Sure.  Have also cc'ed the forum in case anyone has anything else to add.
> 
> 
> Some general notes:
> - We only use EL7041's in production so have done limited testing on EL7031's but they are very similar.
> 
> - Make sure you've got the latest firmware on the module.  Some of the earlier firmwares motion was a little rough.
> 
> - I use the steppers in position controller mode (8012:01 = 3).  In this mode you need to set the target position of the motor every cycle.  It is up to you to calculate your own position / velocity profile.  Steppers don't like sudden movement so you need to ramp up and down the velocity by an acceleration, and you might also want to apply some jerk smoothing.
> 
> - I don't use the modules in Distributed Clock mode.  Never been able to make it work and never had time to figure out why.  Not too much of a problem for my situation.  If you find out how to use it successfully then let us know.
> 
> - Values that I read from a config file and set per module are:
>  Max Current           (8010:01) -> set to suit motor
>  Reduced Current       (8010:02) -> generally I set this to 1/2 of max current
>  Nominal Voltage       (8010:03) -> this module only allows 24V
>  Motor Coil Resistance (8010:04) -> set to suit motor
>  Motor Full Steps      (8010:06) -> ours are 200
>  Max Speed Range       (8012:05) -> generally set to 3 (2400 RPM for a 200 step / rev motor)
>  Reversed              (8012:09) -> if the motor goes the wrong direction set this value
> I set these values before activating the master switching my app to realtime.
> 
> 
> I'm using the following pdo setup:
> 
> ec_pdo_entry_info_t EL7031_pdoEntries[] = {
>    // 0x1602, stepper control (0)
>    {0x7010, 0x01, 1},    // Enable
>    {0x7010, 0x02, 1},    // Reset 
>    {0x7010, 0x03, 1},    // Reduce torque 
>    {0x0000, 0x00, 5},    //   spacer 
>    {0x0000, 0x00, 8},    //   spacer 
> 
>    // 0x1603, stepper pos (5)
>    {0x7010, 0x11, 32},   // Target position
> 
> 
>    // 0x1a03, stepper status (6)
>    {0x6010, 0x01, 1},    // Ready to enable 
>    {0x6010, 0x02, 1},    // Ready 
>    {0x6010, 0x03, 1},    // Warning 
>    {0x6010, 0x04, 1},    // Error 
>    {0x6010, 0x05, 1},    // Moving positive 
>    {0x6010, 0x06, 1},    // Moving negative 
>    {0x6010, 0x07, 1},    // Torque reduced 
>    {0x0000, 0x00, 1},    //   spacer 
>    {0x0000, 0x00, 3},    //   spacer
>    {0x6010, 0x0c, 1},    // Digital input 1 
>    {0x6010, 0x0d, 1},    // Digital input 2 
>    {0x1c32, 0x20, 1},    // Sync error 
>    {0x0000, 0x00, 1},    //   spacer 
>    {0x1803, 0x09, 1},    // *** unknown ***
> 
> };
> 
> ec_pdo_info_t EL7031_pdos[] = {
>    {0x1602, 5, EL7031_pdoEntries + 0},
>    {0x1603, 1, EL7031_pdoEntries + 5},
>    {0x1a03, 14, EL7031_pdoEntries + 6}, };
> 
> ec_sync_info_t EL7031_syncs[] = {
>    {0, EC_DIR_OUTPUT, 0, NULL, EC_WD_DISABLE},
>    {1, EC_DIR_INPUT, 0, NULL, EC_WD_DISABLE},
>    {2, EC_DIR_OUTPUT, 2, EL7031_pdos + 0, EC_WD_DISABLE},
>    {3, EC_DIR_INPUT, 1, EL7031_pdos + 2, EC_WD_DISABLE},
>    {0xff}
> };
> 
> 
> To initialise each module I call (Note: error checking not included):
> 
>  dev->slaveConfig = ecrt_master_slave_config(ecMod->master, dev->alias, dev->position,
>                                              dev->vendorID, 
> dev->productCode);
> 
>  ecrt_slave_config_pdos(dev->slaveConfig, EC_END, EL7031_syncs);
> 
>  dev->m_sdoErrorCode = 
> ecrt_slave_config_create_sdo_request(dev->slaveConfig, 0xA010, 0x00, 
> sizeof(uint8_t));
> 
> 
> Then I configure each of the pdo entries so my app can use them, for each entry I call:
> 
>  offset = ecrt_slave_config_reg_pdo_entry(dev->slaveConfig, EL7031_pdoEntries[_pdoIdx].index,
>                                           pdoEntries [_pdoIdx].subindex,
>                                           
> ecMod->domains[_domIdx].domain, &bitPos);
> 
> 
> Just before going realtime I ensure the Enable (7010:01) value is set to zero.
> 
> 
> To enable a motor I use a state machine that checks for faults and allows for external brakes to be turned on/off etc.  But essentially I do:
> 
>  If enable is requested by the app, reset any current faults:
>    Set FaultReset (7010:02) for a time (I set it for 500ms) then reset
>    If ReadyToEnable (6010:01) then Set Enable (7010:01)
>      Wait until the Ready (6010:02) input is set before letting the 
> app use the motor
> 
>  Monitor the Error (6010:04) status, if there's any error then reset the Enable (7010:01) output and wait for the app to register the fault. 
> 
> 
> If there's any Warning (6010:03) or Error (6010:04) then I check the diagnostic information.  This information is not available via the PDO's so you need to read it via an SDO.  You can either read each A010:01 - A010:0A subindex individually (which I currently do in a state machine) or you can read them using a complete access function call (requiring one of the complete access patches on the dev forum).  Note: this uses dev->m_sdoErrorCode from above.
> 
> 
> Every cycle, set the motors TargetPosition (7010:11), even if its stationary.  Note: this module uses 64-fold micro-stepping.  This means that if your motor is 200 steps per rev, you need to control the TargetPosition with 12800 counts per rev (200 * 64).
> 
> 
> 
> And that's pretty much it.  The hard bits are getting the correct parameters for the motor and providing your own motion profile.
> 
> 
> Have fun,
> Graeme.
> 
> 
> -----Original Message-----
> From: Ewan Houston [mailto:e.houston.1 at research.gla.ac.uk]
> Sent: Tuesday, 11 October 2016 5:02 a.m.
> To: Graeme Foot
> Subject: Beckhoff EL7031
> 
> Hello,
> 
> I am a PhD student at the university of Glasgow. I pulled your name from an ether lab thread that is about the EL7031. I hope you don't mind me being so bold, but how have you got on with programming it? Would you be willing and able to share any of your experience on that front?
> 
> Thanks,
> 
> Ally Houston.