Start-Up/Fault settings

"SetPrm-Unlock before DP-Start-Up" check box

Normally, during DP start-up, the DP master removes the cyclic connections, so that the DP slave device can always recognize that the DP master device has restarted. In redundancy mode, however, it may be specifically desirable for the DP slave device to remain unaware of this, because the switch-over from the primary master to the redundant master should not have any interactions for the DP slave device.

"Operate-Delay [ms]" NumericUpDown control

The DP master device changes automatically, observing the Auto-Clear mode, into the Operate state when the task is started. The transition from Clear to Operate can be delayed with the Operate-Delay time. In the Clear state, all the outputs are set to zero (if the DP slave device does not support Fail_Safe values). or to the Fail_Safe value (if the DP slave device supports Fail_Safe), whereas in the Operate state the outputs have the values specified by the task.

Reaction on Task-Stop

It is possible to specify here whether the DP master device should set the outputs to zero when stopping the PLC or reaching a breakpoint, or should leave them unchanged.

"Clear (Outputs to 0/Default)" option

If this option is selected, the DP master device sets the outputs to zero when the PLC is stopped or at a breakpoint.

"Operate (Outputs unchanged)" option

If this option is selected, the DP master device leaves the outputs unchanged when the PLC is stopped or at a breakpoint.

"Stop (DP communication stopped)" option

If this option is selected, the PROFIBUS stops when the PLC stops or is at a breakpoint. The screenshot shows the task watchdog set to five cycles. Accordingly, PROFIBUS communication stops five task cycles after the PLC has stopped or five task cycles after a breakpoint has been reached.

"Task-Watchdog (Cycles)" NumericUpDown control

In Clear mode the outputs of the slave devices are set to zero or to a fail-safe value. The DP master device automatically switches to Clear mode when it no longer receives an interrupt from an associated task. The DP master device no longer receives an interrupt from the associated task if, for example, the controller has arrived at a breakpoint or if it has crashed. The "Task-Watchdog" NumericUpDown control can be used to set how many missing task cycles are tolerated before the DP master device switches to Clear mode. The "Task Watchdog" setting is independent of the Clear mode setting.

"Windows Watchdog (ms)" NumericUpDown control

The "Windows Watchdog (ms)" NumericUpDown control can be used to set a watchdog time for the Windows operating system. The time unit is milliseconds.

"FreeRun-Mode" check box

If the "FreeRun-Mode" check box is checked, a free-running PROFIBUS mode is set up. The PROFIBUS runs independently of the interrupt signal.

"SetPrm-Unlock at DP-Shutdown" check box

Usually the DP master device disconnects the cyclic connection during a DP shutdown, so that the DP slave device always notices that the DP master device has been stopped. In the redundancy mode, however, it may be desired that the DP slave device does not notice the shutdown, because switching from the primary master device to the redundancy master device for the DP slave device is to be carried out without reaction.

Set Outputs to 0/Default (Clear-Mode)

Clear mode can be disabled. Otherwise, "if a MC-Slave fails" can be set so that the DP master device changes to the Clear state or remains in the Clear state if at least one MC slave device does not respond correctly. A further option is "if a Slave fails", which can be selected so that the DP master device changes to the Clear state or remains in the Clear state if a slave device does not respond correctly. An MC slave device or a slave device does not respond correctly if its DP state is greater than zero.

"Disabled" option

If the option "Disabled" is selected, the Clear mode is disabled.

"if a MC-Slave fails (DP-State > 0)" option

If the option "if a MC-Slave fails" is selected, the DP master device changes to the Clear state or the DP master device remains in the Clear state, if at least one MC slave device does not respond correctly. An MC slave device does not respond correctly if its DP state is greater than zero. The abbreviation MC stands for Motion Control. MC slave devices are clock-synchronous devices that synchronize to a clock telegram.

"if a Slave fails (DP-State > 0)" option

If the option "if a Slave fails" is selected, the DP master device changes to the Clear state or the DP master device remains in the Clear state, if a slave device does not respond correctly. A slave device does not respond correctly if its DP state is greater than zero.

"Set WD individually for each Slave" check box

Here you can select whether the watchdog is to be set individually for each slave device. This is done on the "Profibus" tab of the respective slave device.

"DP-Slave-Watchdog (ms)" NumericUpDown control

If the "Set WD individually for each Slave" check box is not checked, the DP watchdog can be set to a uniform value for all slave devices using the "DP-Slave-Watchdog (ms)" NumericUpDown control.

"Calculate DP-Watchdog" button

Pressing the "Calculate DP-Watchdog" button sets the DP watchdog time of each DP slave device to a suitable value.

"Okay" button

The "Okay" button applies the settings to the configuration and closes the dialog.

"Cancel" button

The "Cancel" button closes the dialog without applying the settings to the configuration.