[etherlab-users] Domain offset overlap

[Steve Hartmann]

Hi Dave,

I do use the bit_position argument.  The first slice (16 channel DI) uses offsets 2 & 3, bit positions 0-7 of each.  The second slice is a 4 channel DO and uses Domain offset 3, bits 0-3.  Also,, the third slice (2 channel AO) has an entry at offset 6, 16 bits while the next slice (2 channel AI) also uses offset 6 with an 8-bit entry.

Regards,

Steven

From: Dave Page <dave.page at gleeble.com<mailto:dave.page at gleeble.com>>
Date: Wednesday, April 9, 2014 5:07 PM
To: Steven Hartmann <shartmann at militho.com<mailto:shartmann at militho.com>>, Etherlab Users <etherlab-users at etherlab.org<mailto:etherlab-users at etherlab.org>>
Subject: Re: [etherlab-users] Domain offset overlap

Hi,

    Sorry, I misinterpreted your message.

    ecrt_slave_config_reg_pdo_entry can produce apparently overlapping offsets when the PDO data is not on even bit boundaries (not divisible by 8).

    You may wish to use the unsigned int *bit_position argument to discover the bit offsets of your data.

        Best regards - Dave

On 09-Apr-14 15:49, Steve Hartmann wrote:
Hi Dave,

Thanks for the reply.  I am not using TwinCAT at all.  Also, please forgive my ignorance, but what is the "LRW command".

I'm not sure how to deal with this with the etherlab stack.  If it give me a domain offset of 3 for two different slices (one input and one output), how do I deal with this overlapped data?

Thanks,

Steven


From: Dave Page <dave.page at gleeble.com<mailto:dave.page at gleeble.com>>
Date: Wednesday, April 9, 2014 2:45 PM
To: Etherlab Users <etherlab-users at etherlab.org<mailto:etherlab-users at etherlab.org>>
Subject: Re: [etherlab-users] Domain offset overlap


    In order to reduce process data size, TwinCAT overlaps the RxPDO and TxPDO for each module, then uses the LRW command to effect the transfer. So, I believe what you're seeing is normal.

        Best regards - Dave Page

On 09-Apr-14 15:41, etherlab-users-request at etherlab.org<mailto:etherlab-users-request at etherlab.org> wrote:

Message: 1
Date: Wed, 9 Apr 2014 19:41:29 +0000
From: Steve Hartmann <shartmann at militho.com><mailto:shartmann at militho.com>
To: Etherlab Users <etherlab-users at etherlab.org><mailto:etherlab-users at etherlab.org>
Subject: [etherlab-users] Domain offset overlap
Message-ID: <CF6B0C97.F827%shartmann at militho.com><mailto:CF6B0C97.F827%shartmann at militho.com>
Content-Type: text/plain; charset="us-ascii"

Hi all,

I have written some code to parse the generated XML file from "ethercat xml" and use that to configure the ethercat stack.  The problem I am having is the output from ecrt_slave_config_ret_pdo_entry produces overlapped offsets.  I also tried using ecrt_slave_config_reg_pdo_entry_pos with the same results.  This is a very simple test rig that has one each of DO, DI, AO, and AI slices - all beckhoff.  I have attached a file which includes the generated XML file, the code in question, and the log output.  Does anyone know what I am doing wrong?

Best regards,

Steven Hartmann


--
________________________________
David Page, Chief Embedded Architect
Dynamic Systems Inc.
PO Box 1234
Poestenkill, NY 12140
Telephone: +1 (518) 283-5350 | Fax: +1 (518) 283-3160 |


--
________________________________
David Page, Chief Embedded Architect
Dynamic Systems Inc.
PO Box 1234
Poestenkill, NY 12140
Telephone: +1 (518) 283-5350 | Fax: +1 (518) 283-3160 |
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