Update: I increased EC_DC_SYNC_WAIT_MS to 50000 (50 seconds). I also set debug level to 1, "ethercat debug 1" and the closest slave 0 (reference clocks) gets to syncing is after about 48 seconds! ("abs_sync_diff" = approximately 1.156 ms). At this point, the value starts to diverge and ends at 1.77 seconds at the 50 seconds mark. *kernel: [14573.717225] EtherCAT DEBUG 0-0: Sync after 47800 ms: 1156111 ns* . . .
*kernel: [14575.919495] EtherCAT DEBUG 0-0: Sync after 49996 ms: 1771539607 ns* *kernel: [14575.923534] EtherCAT WARNING 0-0: Slave did not sync after 50012 ms.* *kernel: [14575.923536] EtherCAT DEBUG 0-0: app_start_time=593344410354840000* *kernel: [14575.923538] EtherCAT DEBUG 0-0: app_time=593344420279840000* *kernel: [14575.923539] EtherCAT DEBUG 0-0: start_time=593344420379840000* *kernel: [14575.923540] EtherCAT DEBUG 0-0: cycle_time=500000* *kernel: [14575.923542] EtherCAT DEBUG 0-0: shift_time=125000* *kernel: [14575.923543] EtherCAT DEBUG 0-0: remainder=0* *kernel: [14575.923544] EtherCAT DEBUG 0-0: start=593344420380465000* *kernel: [14575.923545] EtherCAT DEBUG 0-0: Setting DC cyclic operation start time to 593344420380465000.* *kernel: [14575.928611] EtherCAT DEBUG 0-0: Setting DC AssignActivate to 0x0300.* *kernel: [14575.941292] EtherCAT 0: Domain 0: Working counter changed to 3/6.* *kernel: [14576.000500] EtherCAT DEBUG 0-0: Processing register request...* *kernel: [14576.004685] EtherCAT DEBUG 0-0: Register request successful.* *kernel: [14576.050335] EtherCAT DEBUG 0-0: Now in SAFEOP.* - Is there something wrong with the algorithm used for nudging "abs_sync_diff" towards 0? - If so, why does it work perfectly fine in the userspace, but not in RTAI? Best, Mohsen On Fri, Oct 19, 2018 at 1:05 PM Mohsen Alizadeh Noghani < m.aliza...@gmail.com> wrote: > Hello everyone. > I'm using kernel 3.4.6, RTAI 4.0 and IgH Master 1.5.2. > When running a simple RTAI program > <https://github.com/mohse-n/L7N_EtherLab/blob/master/rtai/rtai_sample.c> > that uses distributed clocks (basically the dc_rtai example), I encounter > the following kernel log: > > *kernel: [ 1891.643677] EtherCAT 0: Link state of ecm0 changed to UP.* > *kernel: [ 1891.647798] EtherCAT 0: 2 slave(s) responding on main device.* > *kernel: [ 1891.647800] EtherCAT 0: Slave states on main device: PREOP.* > *kernel: [ 1891.647837] EtherCAT 0: Scanning bus.* > *kernel: [ 1892.083268] EtherCAT 0: Bus scanning completed in 436 ms.* > *kernel: [ 1892.083271] EtherCAT 0: Using slave 0 as DC reference clock.* > *kernel: [ 1906.700138] EtherCAT: Requesting master 0...* > *kernel: [ 1906.700142] EtherCAT: Successfully requested master 0.* > *kernel: [ 1906.700160] EtherCAT 0: Domain0: Logical address 0x00000000, > 24 byte, expected working counter 6.* > *kernel: [ 1906.700161] EtherCAT 0: Datagram domain0-0-main: Logical > offset 0x00000000, 24 byte, type LRW.* > *kernel: [ 1906.700185] EtherCAT 0: Master thread exited.* > *kernel: [ 1906.700187] EtherCAT 0: Starting EtherCAT-OP thread.* > *kernel: [ 1906.704215] ec_rtai_sample: RT timer started with 3116/3117 > ticks.* > *kernel: [ 1906.704218] ec_rtai_sample: Initialized.* > *kernel: [ 1911.935059] EtherCAT WARNING 0-0: Slave did not sync after > 5000 ms.* > *kernel: [ 1911.946039] EtherCAT 0: Domain 0: Working counter changed to > 3/6.* > *kernel: [ 1914.070216] EtherCAT ERROR 0-0: Failed to set OP state, slave > refused state change (SAFEOP + ERROR).* > *kernel: [ 1914.073870] EtherCAT ERROR 0-0: AL status message 0x002D: "No > Sync Error".* > *kernel: [ 1914.081189] EtherCAT 0-0: Acknowledged state SAFEOP.* > *kernel: [ 1919.308375] EtherCAT WARNING 0-1: Slave did not sync after > 5000 ms.* > *kernel: [ 1919.321187] EtherCAT 0: Domain 0: Working counter changed to > 6/6.* > *kernel: [ 1921.449013] EtherCAT ERROR 0-1: Failed to set OP state, slave > refused state change (SAFEOP + ERROR).* > *kernel: [ 1921.452670] EtherCAT ERROR 0-1: AL status message 0x002D: "No > Sync Error".* > *kernel: [ 1921.459991] EtherCAT 0-1: Acknowledged state SAFEOP.* > *kernel: [ 1921.469158] EtherCAT 0: Slave states on main device: SAFEOP.* > > The slaves (servo drives) would give an alarm related to EtherCAT > communication. > Apparently, the slaves are unable to sync after 5 seconds. But why? > (Note: I have tested the distributed clocks example in userspace and it > works, so I don't think the issue is from the slaves' side.) > Best, > Mohsen >
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