[etherlab-users] el7031 stepper drivers - input registers always zero in PDO, ok in SDO

[Michał Rawlik]

Dear Graeme,

Thank you for your answer!

All my problems were caused by a combination of two facts. First, I accidentally wrote to the domain data address space before reading it out, overwriting some of the data with zeros. Secondly, I did not realise that when writing single bits I should read a byte from the domain data, change only one single bit and then write it again.

Now it works perfectly!

All the best,
Michał


> On 14 Dec 2016, at 23:07, Graeme Foot <Graeme.Foot at touchcut.com> wrote:
> 
> Have a look for any errors in your dmesg log.
> 
> Also, what do your pdoEntries, pdos, syncs structures look like?  Whats your firmware revision?  There are a couple of firmware revisions with different parameter requirements.
> 
> 
> Being a stepper without an encoder, why do you need an actual position?  Set the target position and assume that 5ms later it will be there.
> 
> 
> Regards,
> Graeme.
> 
> 
> 
> -----Original Message-----
> From: etherlab-users [mailto:etherlab-users-bounces at etherlab.org] On Behalf Of Michal Rawlik
> Sent: Wednesday, 14 December 2016 9:28 p.m.
> To: etherlab-users at etherlab.org
> Subject: [etherlab-users] el7031 stepper drivers - input registers always zero in PDO, ok in SDO
> 
> Hi,
> 
> I am having a peculiar issue with the el7031 stepper motor drivers.
> 
> I use them with the predefined PDO assignment "Positioning interface with info data":
> SM2 (output): 0x1601 0x1602 0x1606
> SM3 (input): 0x1A01 0x1A03 0x1A06
> 
> I have no problem with the output PDO entries and can operate motors. However, when I read the input registers I always get 0 (in particular I care about (0x6020 0x01 1 "busy") and (0x6020 0x11 32 "actual position"). At the same time I can get the correct values of those registers via SDO.
> 
> I do not use distributed clocks, have a cycle time of 5ms, run the program in userspace with the ethercat service, on openSUSE Leap 42.2, with generic ethernet driver.
> 
> I had a look in TwinCAT3 and there it is the same - okay in SDO, always zeros in PDO.
> 
> Sincerely,
> Michał
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