Navigation

Time stamp 1ms - ET200M " Time difference between message frame and internal clock may impair accuracy"

Created by: janbar_k at: 8/27/2013 11:32 PM (6 Replies)

Rating (2)

Thanks 2

7 Entries

8/27/2013 11:32 PM

Rate (0)

janbar_k

Experienced Member

Joined: 1/23/2013

Last visit: 10/17/2024

Posts: 38

Rating:

(1)

Dear Sirs!

We have PCS7 V8.0 UPD1 system configured with several AS with ET200M configured for "High-precision time stamping with 1 ms accuracy" as described in manuals of PCS7.

We are facing problem that we receive to alarms to OS like:

14:08:56.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going
14:08:56.024	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming	22
14:08:56.981	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming
14:08:57.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going	21
14:09:49.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going
14:09:49.033	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming	31
14:09:49.972	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming
14:09:50.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going	30
14:10:47.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going
14:10:47.033	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming	31
14:10:47.973	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming
14:10:48.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going	29
14:11:42.001	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going
14:11:42.033	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming	32
14:11:42.973	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming
14:11:43.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going	29
14:12:42.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going
14:12:42.033	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming	31
14:12:42.973	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming
14:12:43.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going	29
14:13:41.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going
14:13:41.033	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming	31
14:13:41.973	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming
14:13:42.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going	29
14:14:34.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going
14:14:34.033	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming	31
14:14:34.973	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming
14:14:35.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going	29
14:15:33.002	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Going
14:15:33.033	IM 1/63: Time difference between message frame and internal clock may impair accuracy	Comming	31

We use Siemens clock TC100, S7-400 with CPU416-2, dual optical ring with scalance ethernet switchs.

Simatic clock TC100 is configured as "Simatic time", same also for AS station.

AS send time to DP in 1s intervals.

CPU load is about 75%

As far I understand manual this messages (in manual described as "Time difference between the messageframe time stamp and the real-time clock may cause inaccuracy") come in pair and tells:

- "comming" message with time before time synchronization

- "going" message with time after time synchronization

In our case time is each minute corrected 2 times for a difference about 20-35ms.

Shouldn't this messagesmore rarely?

Any idea what could be wrong?

In another test we change to 10s period of sending time to DP and messages arrivedmore rarely, but also a lot of them.

This problem is further notifiend in another problem of receiving changes(messages of EVENT_TS) of digital input to OS.

Attachment

architecture.pdf (160 Downloads)

9/24/2013 9:43 PM	Rate (0)
janbar_k Experienced Member Joined: 1/23/2013 Last visit: 10/17/2024 Posts: 38 Rating: (1)	Problem was narrowed to Siclock TC100. Time to time happens that is some trafic on ethernet and message which should go at full second and 50 ms is delayed and transmited again(normaly in next 20-35ms). Device in case of network trafic emit message with original timestamp (because use standard TCP/IP stack). ET200M connected to S7-400 see difference in his clock and clock received by S7-400/TC100. At first retransmitted time message ET200M put clock back, next time message is normaly emitted at correct time and ET200M sets clock forward. Simatic CP443-1, when work as Simatic mode time master is capable in case of network trafic emit correct (actual) time. Support in this case recomends use of NTP which precision can vary. Simatic time guaranties that synchronized CPU is +-1ms accuratly synchronized.

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users dchartier

2/9/2017 8:29 AM	Rate (0)
jmonge Posts: 1 Rating: (0)	Hello, how did you fix this problem? In my case: I've got clock TC400, S7-400 with CPU417-4H, optical ring with scalance ethernet switchs. Simatic clock TC400 is configured as "S7 time", same also for AS station. AS send time to DP in 10 s intervals. The message appears in 10 s intervals, around six times in an hour.
jmonge Posts: 1 Rating: (0)
Suggestion To thank Quote Answer

2/9/2017 8:42 AM	Rate (1)
janbar_k Experienced Member Joined: 1/23/2013 Last visit: 10/17/2024 Posts: 38 Rating: (1)	We didn't use SIMATIC time as time synchronization source. We use NTP. BR JP

Suggestion To thank Quote Answer

3/8/2021 3:31 PM	Rate (0)
Sebastian P Advanced Member Joined: 10/12/2016 Last visit: 12/16/2024 Posts: 21 Rating: (1)	janbar_k We didn't use SIMATIC time as time synchronization source. We use NTP. BR JP Hello janbar_k, in our plant we are using NTP, and we have the same problem. Could you give some detail of how you have solved the problem?

Suggestion To thank Quote Answer

3/10/2021 6:39 AM	Rate (0)
hosein8419 Bronze Member Joined: 9/1/2017 Last visit: 12/24/2024 Posts: 156 Rating: (19)	Hi unknown user If the "High-precision time stamping" function is used for selected signals in an automation system, then the direct time synchronization of the plant bus via a SICLOCK TC x00 central plant clock is required. If the SICLOCK TC x00 central plant clock fails, the time accuracy is not sufficient for the high-precision time stamping. The chronological order of the signals displayed remains intact. Anyway if your plant bus synchronized in simatic mode you can define your os servers as cooperative time master incase of losing central time master(siclock for example). Regards Hosein Attachment ps7tsy_b_en-US (1).pdf (113 Downloads)

Suggestion To thank Quote Answer

3/10/2021 1:41 PM	Rate (1)
Sebastian P Advanced Member Joined: 10/12/2016 Last visit: 12/16/2024 Posts: 21 Rating: (1)	Hello We have everything synchronized by the NTP method, and I do not want to modify it, my question is: what should I check to avoid this repetitive message? SICLOCK TC-400 connected to the Plant Bus. Redundant AS, with CP 443-1 -> 443-5 Ext. -> IM 153-2.

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users hossein_sh

Share this page:

Share this page on...

Created by: janbar_k at: 8/27/2013 11:32 PM (6 Replies)

Rating (2) Thanks 2

7 Entries

Attachment

This contribution was helpful to

Attachment

This contribution was helpful to

7 Entries

Follow us on

Rating (2)

Thanks 2