Frequently asked questions

The following are frequently asked questions about access and control modes.

Do access modes affect control modes?

It does. SetAxisAccessMode has the higher prioirity. After you set an access mode, you can only use the control modes the selected access mode provides. For example, the access mode is accessVel. You can use modeManual, modeDirectVel, modeMasterIntVel, and modePidVel. You can use SetAxisControlMode to change between Vel modes, but you cannot change to a Pos or Tor mode.

The default access mode is accessVelPos if SetAxisAccessMode is not called. Each access mode has a default control mode used until you call SetAxisControlMode. For accessPos, accessPosVel, and accessPosVelTor, the default mode is modeMaterIntPos. For accessVel, accessVelPos, and accessVelPosTor, the default mode is modeMasterIntVel. For accessTor, the default mode is modeMasterIntTor.

Is it necessary to set an access mode?

No. The default access mode is accessVelPos. If you want to change the control mode while the axis is running, we suggest you enable EnableSynchronizedControlMode to allow the control mode to be changed using the PDO.

Not all drives support the selected access mode or switching the mode using the PDO. If you select an access mode that is incompatible with the drive, the closest compatible mode will be used. If you try to set a control mode that is not supported by the current access mode, SetAxisControlMode will return an error. If the synchronized control mode is not enabled and you change the control mode while the drive is enabled, there may be unexpected behavior during the transition.