PSCCM22AAN 16418-5312 output module

Using a terminal program, the state of a limit switch can be printed to the screen with the command, MG _LFx or MG _LRx. This prints the value of the limit switch operands for the 'x' axis. The logic state of the limit switches can also be interrogated with the TS command. For more details on TS, _LFx, _LRx, or MG see the Command Reference.

The Find Edge routine is initiated by the command sequence: FEX, BGX(where X could be any axis on the controller, X,Y,Z, or W). The Find Edge routine will cause the motor to accelerate, then slew at constant speed until a transition is detected in the logic state of the Home input. The direction of the FE motion is dependent on the state of the home switch. Refer to the CN command to set the correspondence between the Home Input voltage and motion direction. The motor will decelerate to a stop when a transition is seen on the input. The acceleration rate, deceleration rate and slew speed are specified by the user, prior to the movement, using the commands AC, DC, and SP. It is recommended that a high deceleration value be used so the motor will decelerate rapidly after sensing the Home switch.

Home Switch Input

 Homing inputs are designed to provide mechanical reference points for a motion control application. A transition in the state of a Home input alerts the controller that a particular reference point has been reached by a moving part in the motion control system. A reference point can be a point in space or an encoder index pulse. The Home input detects any transition in the state of the switch and changes between logic states 0 and 1, corresponding to either 0V or 5V depending on the configuration set by the user (CN command). The CN command can be used to customize the homing routine to the user’s application. There are three homing routines supported by the DMC-21x2/21x3: Find Edge (FE), Find Index (FI), and Standard Home (HM).

The Find Index routine is initiated 

by the command sequence: FIX, BGX(where X could be any axis on the controller, X,Y,Z, or W). Find Index will cause the motor to accelerate to the user-defined slew speed (SP) at a rate specified by the user with the AC command and slew until the controller senses a change in the index pulse signal from low to high. The motor then decelerates to a stop at the rate previously specified by the user with the DC command. Although Find Index is an option for homing, it is not dependent upon a transition in the logic state of the Home input, but instead is dependent upon a transition in the level of the index pulse signal.