PROFIsafe Watchdog tolerance

Booster
Posts: 4
Joined: 05 Mar 2024, 12:24

PROFIsafe Watchdog tolerance

Post

The PROFIsafe Tests include tests with the Safetylayer-Tester.
In documentation of Safetylayer-Tester, the watchdog test is required for certification.
It should be checked whether the measured times are within tolerance.

Maximum value = ((watchdog value + 10%) + device cycle time + inaccuracy of
measurement)

Does the Device-Cycle-Time correspond to the Device-Acknowledgment-Time?
Or does one of these times also include other times such as the transmission time?
DanielS
PROFINET Expert
Posts: 7
Joined: 19 Sep 2023, 16:03

Re: PROFIsafe Watchdog tolerance

Post

Booster wrote: 26 Nov 2024, 10:44 The PROFIsafe Tests include tests with the Safetylayer-Tester.
In documentation of Safetylayer-Tester, the watchdog test is required for certification.
It should be checked whether the measured times are within tolerance.

Maximum value = ((watchdog value + 10%) + device cycle time + inaccuracy of
measurement)

Does the Device-Cycle-Time correspond to the Device-Acknowledgment-Time?
Or does one of these times also include other times such as the transmission time?
Hi Booster,

no these are two different Times. The Device-Cycle-Time is the cycle time the time the device communicates with the F-Host e.g. 1ms. The Device-Acknowledgment-Time is the time the device needs to react on a changed MonitoringNumber (MNR). There is no other time included such as transmission transmission time.

BR
Daniel
Booster
Posts: 4
Joined: 05 Mar 2024, 12:24

Re: PROFIsafe Watchdog tolerance

Post

DanielS wrote: 27 Nov 2024, 13:46
Booster wrote: 26 Nov 2024, 10:44 The PROFIsafe Tests include tests with the Safetylayer-Tester.
In documentation of Safetylayer-Tester, the watchdog test is required for certification.
It should be checked whether the measured times are within tolerance.

Maximum value = ((watchdog value + 10%) + device cycle time + inaccuracy of
measurement)

Does the Device-Cycle-Time correspond to the Device-Acknowledgment-Time?
Or does one of these times also include other times such as the transmission time?
Hi Booster,

no these are two different Times. The Device-Cycle-Time is the cycle time the time the device communicates with the F-Host e.g. 1ms. The Device-Acknowledgment-Time is the time the device needs to react on a changed MonitoringNumber (MNR). There is no other time included such as transmission transmission time.

BR
Daniel

Hey Daniel,

thank you for your answer!

How are the wd_min and wd_max values measured in detail?
Is the watchdog started and then monitored cyclically to determine whether it has been triggered? (wd_max)
And how is the wd_min value measured?

Thank you very much in advance for your answer!
DanielS
PROFINET Expert
Posts: 7
Joined: 19 Sep 2023, 16:03

Re: PROFIsafe Watchdog tolerance

Post

Booster wrote: 27 Nov 2024, 16:41
DanielS wrote: 27 Nov 2024, 13:46
Booster wrote: 26 Nov 2024, 10:44 The PROFIsafe Tests include tests with the Safetylayer-Tester.
In documentation of Safetylayer-Tester, the watchdog test is required for certification.
It should be checked whether the measured times are within tolerance.

Maximum value = ((watchdog value + 10%) + device cycle time + inaccuracy of
measurement)

Does the Device-Cycle-Time correspond to the Device-Acknowledgment-Time?
Or does one of these times also include other times such as the transmission time?
Hi Booster,

no these are two different Times. The Device-Cycle-Time is the cycle time the time the device communicates with the F-Host e.g. 1ms. The Device-Acknowledgment-Time is the time the device needs to react on a changed MonitoringNumber (MNR). There is no other time included such as transmission transmission time.

BR
Daniel

Hey Daniel,

thank you for your answer!

How are the wd_min and wd_max values measured in detail?
Is the watchdog started and then monitored cyclically to determine whether it has been triggered? (wd_max)
And how is the wd_min value measured?

Thank you very much in advance for your answer!


Hi Booster,

no these are two different Times. The Device-Cycle-Time is the cycle time the time the device communicates with the F-Host e.g. 1ms. The Device-Acknowledgment-Time is the time the device needs to react on a changed MonitoringNumber (MNR). There is no other time included such as transmission transmission time.

BR
Daniel
DanielS
PROFINET Expert
Posts: 7
Joined: 19 Sep 2023, 16:03

Re: PROFIsafe Watchdog tolerance

Post

DanielS wrote: 28 Nov 2024, 12:47
Booster wrote: 27 Nov 2024, 16:41


Hi Booster,

no these are two different Times. The Device-Cycle-Time is the cycle time the time the device communicates with the F-Host e.g. 1ms. The Device-Acknowledgment-Time is the time the device needs to react on a changed MonitoringNumber (MNR). There is no other time included such as transmission transmission time.

BR
Daniel

Hey Daniel,

thank you for your answer!

How are the wd_min and wd_max values measured in detail?
Is the watchdog started and then monitored cyclically to determine whether it has been triggered? (wd_max)
And how is the wd_min value measured?

Thank you very much in advance for your answer!

Hi Booster,

the layer tester establishes a connection to the device and starts safety data exchange. At a specific point the togglebit is not changed anymore and this results in a F_WD_Timeout. This happens a few times and the tester is calculating the time between stop changing togglebit and the change in the StatusByte from the device when it realizes the Timeout. Now you have a few measurements where you got a min and a max value.

Best regards,
Daniel
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