Stop Procedure Triggers

PAtools applications offer the following stop procedures to shut down the test bench:

  • Soft stop (normal stop)
  • Hard stop (normal stop)
  • Emergency stop

The following distinctions are made between normal and emergency stops.

Normal Stop Process

The normal stop processes (soft and hard stops) shut down the test bench while protecting the test specimen as much as possible.

A normal stop is based on the standard control mode, n/n. If the test bench controller that is integrated in the powertrain application is used, the torque limits are reduced in a normal stop in such a way that the test specimen is protected.

If the test bench cannot be brought to a standstill by normal stop in the required time, a controller fast stop is triggered.

Emergency Stop Process

An emergency stop is triggered either by the system or by the user.

If the emergency stop is triggered automatically by the system, the switching off is left to the drive converter. In this case, it is recommended that you leave the drives to coast without a load, since emergency stop is triggered by the system only if a controlled switching off (normal stop) is no longer possible.

If an emergency stop is triggered manually by pressing the emergency stop button, the system tries to shut down the test bench using normal stop. Only at a time specified in the emergency stop module (e.g., 5 seconds), is the emergency stop request sent to the drive converter.

In case of an emergency stop, the DC power supply and the DUT power inverter itself are also switched off.

Stop Procedure Triggers in PAtools

These stop procedures are prompted by different types of triggers. The triggers and stop procedures are standardized and consistent throughout the standardized PAtools applications.

This shutdown procedure ensures that the DUT is handled as carefully as possible.

Using the message system, you can trigger the stop procedure triggers in the following table.

Table 9. Stop Procedure Triggers
Stop Procedure Trigger
Soft stop Message_ErrorSoft
Hard stop Message_ErrorHard
Emergency stop Message_ErrorEmergency
Important NI recommends using the soft stop (Message_ErrorSoft) within the PCU application only.

The logic for the PCU shutdown procedure is shown in the following figure.

Figure 27. PCU Shutdown Logic
1378

Figure definitions:

  • b2b—Back-to-back.
  • b2b normal—Two equal DUT motors or other DUTs (e.g., two similar electric axles) are coupled with/linked to each other. In this case, the shutdown is performed in the currently selected control mode. Keep the control mode in case of shutdown.
  • b2b master—Two DUT motors are linked to each other. One of them is more powerful (e.g., higher torque). The shutdown is performed by using this master DUT motor to ramp down in control mode speed.
  • b2b no—Normal e-motor test bench with a DUT e-motor linked to a test bench drive. In this case, the shutdown is performed by using the test bench drive to ramp down the controlled speed.