Galil Motion Control DMC-21 5 Series User Manual page 25

Each input from the auxiliary encoder is a differential line receiver and can accept voltage levels between ±12 V.
The inputs have been configured to accept TTL level signals. To connect TTL signals, simply connect the signal to
the + input and leave the - input disconnected. For other signal levels, the '-' input should be connected to a
voltage that is ~½ of the full voltage range (for example, connect the '-' input to the 5 volts on the Galil if the signal
is 0 - 12V logic).
Example:
A DMC-2115 has one auxiliary encoder. This encoder has two inputs (channel A and channel B). Channel A input is
mapped to input 81 and Channel B input is mapped to input 82. To use this input for 2 TTL signals, the first signal
will be connected to AA+ and the second to AB+. AA- and AB- will be left unconnected. To access this input, use the
operand and @IN[82].
@IN[81]
NOTE: The auxiliary encoder inputs are not available for any axis that is configured for stepper motor.
Electrical Specifications
Maximum Voltage
Minimum Voltage
'+' inputs are internally pulled-up to 5V through a 4.7kΩ resistor
'-' inputs are internally biased to ~1.3V
Limit Switch Inputs
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.
The motor will remain on (in a servo state) after the limit switch has been activated and will hold motor position.
The controller can be configured to disable the axis upon the activation of a limit switch, see the OE command in
the command reference for further detail.
When a forward or reverse limit switch is activated, the current application program that is running in thread zero
will be interrupted and the controller will automatically jump to the
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 for Monitoring Conditions are discussed in
Chapter 7 Application Programming.
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. Any attempt at further motion before the logic state
has been reset will result in the following error: "22 - Begin not possible due to limit switch" error.
The operands, _LFm and _LRm, contain the state of the forward and reverse limit switches, respectively (m
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, or MG_LRm. This prints the value of the limit switch operands for the m axis. The logic state of
MG_LFm
the limit switches can also be interrogated with the
Reference.
Home Switch Inputs
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.
Chapter 3 Connecting Hardware ▫ 20
pulled up to 5V through a 7.1kΩ resistor
pulled down to GND through a 2.5kΩ resistor
12 V
DC
-12 V
DC
#LIMSWI
command. For more details on
TS
subroutine if one exists. This is a
see the Command
TS
DMC-21x5 User Manual 1.0a1