Galil DMC-2X00 user manual Overview, Using Optoisolated Inputs, Limit Switch Input

Chapter 3 Connecting Hardware

Overview

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The DMC-2x00 provides opto-isolated digital inputs for forward limit, reverse limit, home, and abort signals. The controller also has 8 opto-isolated, uncommitted inputs (for general use) as well as 8 TTL outputs and 8 analog inputs configured for voltages between +/- 10 volts.

Controllers with 5 or more axes have an additional 8 opto-isolated inputs and an additional 8 TTL outputs.

This chapter describes the inputs and outputs and their proper connection.

If you plan to use the auxiliary encoder feature of the DMC-2x00, you will require a separate encoder cable and breakout - contact Galil Motion control

Using Optoisolated Inputs

Limit Switch Input

The forward limit switch (FLSx) inhibits motion in the forward direction immediately upon activation of the switch. The reverse limit switch (RLSx) inhibits motion in the reverse direction immediately upon activation of the switch. If a limit switch is activated during motion, the controller will make a decelerated stop using the deceleration rate previously set with the DC command. The motor will remain “ON” (in a servo state) after the limit switch has been activated and will hold motor position.

When a forward or reverse limit switch is activated, the current application program that is running will be interrupted and the controller will automatically jump to the #LIMSWI subroutine if one exists. This is a subroutine which the user can include in any motion control program and is useful for executing specific instructions upon activation of a limit switch. Automatic Subroutines are discussed in Chapter 6.

After a limit switch has been activated, further motion in the direction of the limit switch will not be possible until the logic state of the switch returns back to an inactive state. This usually involves physically opening the tripped switch. Any attempt at further motion before the logic state has been reset will result in the following error: “022 - Begin not possible due to limit switch” error.

The operands, _LFx and _LRx, contain the state of the forward and reverse limit switches, respectively (x represents the axis, A,B,C,D etc.). The value of the operand is either a ‘0’ or ‘1’ corresponding to the logic state of the limit switch. Using a terminal program, the state of a limit switch can be printed to the screen with the command, MG _LFx or MG _LFx. 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 see the Command Reference.

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