Active high wiring.

Example 2: Active Low

In the case of an active low drive enable input, the drive is "enabled" when the Amp Enable signal is low.

 

The diagram below shows how to connect a fail-safe circuit. Normally, the controller's output transistor is inactive. When the transistor is inactive (OFF), the resistor pulls the Amp Enable Input up to +5V or +24V, disabling the drive. When the transistor is active (ON), the Amp Enable Input is pulled to ground, enabling the drive.

Setting Amp Enable and Polarity from Motion Console

When operating drive amplifiers with Motion Console, you must indicate the following:

• the state of the amplifier: Enabled or Disabled (unchecked)
• the polarity of the amplifier: Inverted or Normal (unchecked)

This is done using the Amp Enable and Amp Polarity parameters within the Motor Summary / Config tab page:

The Amp Enable parameter is for use with drives equipped with enable lines. On such drives, the amplifier responds to commands only when the Amp Enable parameter is set to Enabled. If Amp Enable is not enabled, the amplifier will not respond to commands.

For fail-safe operation, the Amp Enable logic is determined by the wiring between the controller and drive. In this case, the Amp Polarity should be set to Inverted.

The Amp Polarity parameter tells the XMP controller whether the output transistor should be normally inactive, to disable the drive (Inverted) or normally active, to disable the drive (Normal). Only the "Inverted" Amp Polarity setting supports fail-safe wiring, and is strongly recommended.

Active LOW Drive Enable Wiring

Active HIGH Drive Enable Wiring

Amplifier Enabling from the MPI

Amplifier enabling is a crucial safety issue in the design of your application. Your system should be designed to anticipate the possibility of a sudden loss of power and/or connectivity to the controller and/or drive.

To make a full accounting of your motion system's safety features, you must also address the system's mecahnical dynamics with a disabled drive. (A disabled drive does NOT necessarily mean that all motion will be stopped!) In many cases, the use of automatic, dynamic braking is recommended for high-mass, high-speed loads.

Determining whether an amplifier remains enabled or disabled with the controller powered OFF depends upon several factors:

• Does the drive have an Amp Enable line? (Not all drives do. Check this!) Is the drive's Amp Enable line internally configured as active-high or active low?
• How is the Amp Enable line wired between the controller and the drive? With power OFF to the controller, does wiring pull the drive's Amp Enable line HIGH or LOW?
• How is the Amp Enable line configured on the controller when it is powered? Is the Amp Enable output transceiver normally ON or OFF? Is the Amp Enable output inverted?
• Does the application software maintain the Amp Enable line in an enabled state when running? Is the controller's position error limit configured for Abort (disables the drive)? Does the application respond to states, disabling or enabling the drive?

  State logic for active high and active low drives.

  DRIVE	WIRING	STATE
  How is the drive's Amp Enable line internally configured?	With power to the controller OFF, current to the drive's Amp Enable line is...	When power to the controller is OFF, the drive is...
  Active High	High	Enabled
  	Low	Disabled*
  Active Low	High	Disabled*
  	Low	Enabled
  * Recommended configuration.

 

To Pull-up Logic

To Pull-down Logic