PROFIsafe Watchdog tolerance

[Booster]

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]

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]

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]

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]

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

[Booster]

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

Hey,

the layer tester uses the watchdog measurement to check whether the watchdog timeout is triggered within a specified time, right?
According to the layer tester documentation, the Device Cycle Time is used to determine the upper limit value.

When exactly does tge time measurement start?

Does the measurement start when the last "valid" (togglebit is no longer changed) control byte is sent by the CP1616? Or doeas the measurement start when the last "valid" status byte is received by CP1616?

If the measurement is started by sending the control byte, i don't understand why the Device Cycle Time is used for the upper limit range. Shouldn't the Device Acknowledgment Time be used in this case?

My thought behind this is that the information from the next MNR must first be processed before the watchdog timeout in the status byte is handled.

Thanks for the answer!

[DanielS]

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

Hey,

the layer tester uses the watchdog measurement to check whether the watchdog timeout is triggered within a specified time, right?
According to the layer tester documentation, the Device Cycle Time is used to determine the upper limit value.

When exactly does tge time measurement start?

Does the measurement start when the last "valid" (togglebit is no longer changed) control byte is sent by the CP1616? Or doeas the measurement start when the last "valid" status byte is received by CP1616?

If the measurement is started by sending the control byte, i don't understand why the Device Cycle Time is used for the upper limit range. Shouldn't the Device Acknowledgment Time be used in this case?

My thought behind this is that the information from the next MNR must first be processed before the watchdog timeout in the status byte is handled.

Thanks for the answer!

Hi,

sorry for the late reply I was trying to find out how the tester does this exactly.
I have to say that I´m not able to give you an exact answer as the tester is a black box and I know that the tester gives command to the CP1616 card but what exactly the card does is not possible to say for me.

My understanding is the following:
Tester changes ToggleBit in ControlByte (internally Timestamp) -> F_Watchdog_Time in Device is resettet. -> Tester does not change the ToggleBit in the ControlByte -> F_Watchdog_Time is running out in the device -> Device sets StatusByte to 0x18 (new Timestamp) -> Difference between two timestamps is the measured time.

BR
Daniel

[Booster]

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

Hey,

the layer tester uses the watchdog measurement to check whether the watchdog timeout is triggered within a specified time, right?
According to the layer tester documentation, the Device Cycle Time is used to determine the upper limit value.

When exactly does tge time measurement start?

Does the measurement start when the last "valid" (togglebit is no longer changed) control byte is sent by the CP1616? Or doeas the measurement start when the last "valid" status byte is received by CP1616?

If the measurement is started by sending the control byte, i don't understand why the Device Cycle Time is used for the upper limit range. Shouldn't the Device Acknowledgment Time be used in this case?

My thought behind this is that the information from the next MNR must first be processed before the watchdog timeout in the status byte is handled.

Thanks for the answer!

Hi,

sorry for the late reply I was trying to find out how the tester does this exactly.
I have to say that I´m not able to give you an exact answer as the tester is a black box and I know that the tester gives command to the CP1616 card but what exactly the card does is not possible to say for me.

My understanding is the following:
Tester changes ToggleBit in ControlByte (internally Timestamp) -> F_Watchdog_Time in Device is resettet. -> Tester does not change the ToggleBit in the ControlByte -> F_Watchdog_Time is running out in the device -> Device sets StatusByte to 0x18 (new Timestamp) -> Difference between two timestamps is the measured time.

BR
Daniel

Hey Daniel,

thank's for your answer!
The calculation of the tolerance time for watchdog-timeout is a black box for me... I'm not sure if the term ‘Device-Cycle-Time’ in the layertester documentation is the right one...

But thank you very much for your help!