[etherlab-users] rtai_rtdm_dc example, "error: system_time_base less than system time" message

[Bilko AS, Oguz Dilmac]

Hi,

We solved the problem last week.
It turned out we have to place the same kind of bechoff IO modules next 
to each other.

In the group of modules which connected to a EK1100 we had 17 modules. 
In this group, we had four EL1008 one after the other; Then a few other 
modules; Then one EL1008; again afew more modules and finally two more 
EL1008. When we group all the EL1008 modules in a row, the problem 
disappeared.

Best regards,
Oguz.

26.1.2016 01:49 tarihinde Graeme Foot yazdı:
>
> Hi,
>
> The “system_time_base less than system time” is from the rtai_rtdm_dc 
> example code.
>
> In the example it looks like system_time_base is initialised to zero 
> and adjusted by a maximum of +-1001 each cycle.  A value of 
> -58905492552780 indicates that system_time_base is not being correctly 
> initialised or is being corrupted with any other values.
>
> As to the motor “knock” every now and then, this is due to the motors 
> dc clock not being correctly synchronized with the masters cycle 
> time.  It is due to the master either missing or sending two messages 
> to the amps in one cycle every now and then.  Sort out your dc timing 
> and the knock will go away.
>
> Regards,
>
> Graeme.
>
> *From:*etherlab-users [mailto:etherlab-users-bounces at etherlab.org] *On 
> Behalf Of *Bilko AS, Oguz Dilmac
> *Sent:* Tuesday, 26 January 2016 4:37 a.m.
> *To:* etherlab-users at etherlab.org <mailto:etherlab-users at etherlab.org>
> *Subject:* [etherlab-users] rtai_rtdm_dc example, "error: 
> system_time_base less than system time" message
>
> Hi,
>
> We have been using EtherCAT master 1.5.2 for about two years. We have 
> successfully implemented 4 machines. Each has 5 Kollmorgen AKD servo 
> drives and some Beckhoff IO modules.
> Now we are implementing a new machine. On this machine we usually get 
> the following messages:
> ...
> "system2count() error: system_time_base less than system time 
> (system_time_base: -58905492552780, time:680659495658"
> "system2count() error: system_time_base less than system time 
> (system_time_base: -58905492552858, time:680660495658"
> "system2count() error: system_time_base less than system time 
> (system_time_base: -58905492552936, time:680661495658"
> "system2count() error: system_time_base less than system time 
> (system_time_base: -58905492553014, time:680662495658"
> ...
>
> We implemented our system based on the *rtai_rtdm_dc* example. Only 
> main difference is, we use kernel modules with RTAI instead of LXRT 
> user mod.
> We are using "cyclic positon" (8) mode with distributed clock.
> We choose the first DC capable device as the reference clock by 
> calling *ecrt_master_select_reference_clock(master, 0);
> *The first node on the bus is a AKD servo drive.
>
> The error occurs from the startup and not disappear until we reboot 
> the PC and the drives.
> When the error occurs, it seems sometimes drives can't update the new 
> position reference. Therefore, if it is moving, it tries to stop for 
> one sample and continues to the new reference at the next sample.
> This causes a loud "knock" sound on the machine.
>
> We didn't get this message with previous 4 machines.
> We tried different FW versions of the AKD drives. Also tried to change 
> the bus node order of the drives. But nothing changed.
> Do you know what can be the cause for this message? How can we fix the 
> problem?
>
> Best regards,
> Oguz.
>
> -- 
>
> Oguz Dilmac
> ARGE Bolumu
> Bilko AS, R&D Department
> ====================================
> Perpa Ticaret Merkezi B Blok Kat 13 Nr. 2568
> TR-34384 Okmeydani Istanbul Turkey
> Tel : +90 212 220 07 40  Fax :   +90 212 210 47 01
> e-mail :odilmac at bilko-automation.com <mailto:odilmac at bilko-automation.com>
> web site :http://www.bilko-automation.com
>          
>
>
> _______________________________________________
> etherlab-users mailing list
> etherlab-users at etherlab.org
> http://lists.etherlab.org/mailman/listinfo/etherlab-users

-- 

Oguz Dilmac
ARGE Bolumu

Bilko AS, R&D Department
====================================
Perpa Ticaret Merkezi B Blok Kat 13 Nr. 2568
TR-34384 Okmeydani Istanbul Turkey
Tel : +90 212 220 07 40  Fax :   +90 212 210 47 01
e-mail : odilmac at bilko-automation.com
web site : http://www.bilko-automation.com
	

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