[etherlab-users] Problems with Pdo entry with index 0x0000

[Jordi Blanch]

Dear Richard,

yes, we were confusing configuration and mapping. Thank you very much
for your explanation, now I think it's clear for us.

Best regards.

On Fri, 08 Nov 2013 12:31:59 +0100, Richard Hacker <ha at igh.de> wrote:
> You have to add the gaps to the configuration but you cannot map them
> to a variable! I think you are confusing configuration and mapping.
> 
> Configuration is done using ecrt_slave_config_pdos() to inform the
> master how the slave PDO is constructed. This configuration may
> include gaps which are used to align PDO's to natural borders.
> 
> However, gaps can not be mapped to a process variable inside your
> program i.e. with ecrt_domain_reg_pdo_entry(). That means you can not
> access the values in these gaps.
> 
> Thus I was wrong last time. Since ecrt_domain_reg_pdo_entry_list()
> can only access real PDO's (having a non-zero index), the
> functionality inside the master is correct.
> 
> - Richard
> 
> 
> Am 11/06/2013 09:17 AM, schrieb Jordi Blanch:
>> Hello,
>>
>> we thought that it was necessary to add GAPs entries to the list,
>> otherwise the master couldn't calculate the bit offset of the data
>> received from ethercat frames because every ec_pdo_entry_reg_t relates
>> it's data position to the previous ec_pdo_entry_reg_t item, isn't it?
>> Also, I think I remember we already tried not to register GAPs and then
>> we were not receiving the data correctly (but I'm talking from my
>> memory...).
>>
>> Thank you.
>>
>> On Tue, 5 Nov 2013 17:48:03 +0100, Florian Pose <fp at igh.de> wrote:
>>> Hello,
>>>
>>> On Tue, Nov 05, 2013 at 04:36:26PM +0100, Richard Hacker wrote:
>>>> I understand your problem when registering gaps. Actually the code
>>>> in the ethercat master does not do the right thing by testing on
>>>> index. Actually it should be testing for reg->bit_position instead.
>>>> I will communicate this with the developer.
>>>
>>> sorry Richard. I have to be contradictory. ;-)
>>>
>>> Please let me clarify this: There should be no gaps in the list passed
>>> to ecrt_domain_reg_pdo_entry(), because gaps are no actual PDO entries
>>> and can not be uniquely identified via PDO entry index and
>>> subindex, and thus can not be registered.
>>>
>>> Note that gaps are perfectly valid in context of the PDO configuration
>>> (see ecrt_slave_config_pdos() and friends).
>>>
>>> Best regards,
>>> Florian
>>> _______________________________________________
>>> etherlab-users mailing list
>>> etherlab-users at etherlab.org
>>> http://lists.etherlab.org/mailman/listinfo/etherlab-users
>>
> 
> Mit freundlichem Gruß
> 
> Richard Hacker

-- 
Jordi Blanch Carles
Unidad de Ensayo y Control

ENCOPIM S.L.
Carretera de Ripollet a Santiga, 104.
P.I. Els Pinetons
E-08291 RIPOLLET (Barcelona)
Tel: (+34) 935 94 23 47
Fax: (+34) 935 94 64 15

==========================================================
La información contenida en la presente transmisión es confidencial y
su uso únicamente está permitido a su(s) destinatario(s). Si Ud. no es
la persona destinataria de la presente transmisión, rogamos nos lo
comunique de manera inmediata por teléfono (+34 935 942 347) y destruya
cualquier copia de la misma (tanto digitales como en papel).

The information contained in this transmission is confidential and is
intended only for the use of the addressee(s). If you are not the
designated recipient of this transmission, please advise us immediately
by telephone (+34 935 942 347) and destroy any copies (digital and
paper).
======================================================