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Signal Input Circuits
IMS-MN-LMDE42C_A
Liberty MDrive Ethernet TCP/IP
Signal Input Wiring and Usage Examples
Mechanical Switches
Sinking Operation: In the schematic below, the inputs will float at a 24V level (HIGH), then go to
ground (LOW) when the switch is closed.
Sourcing Operation: The configuration shown below can be switched to a sourcing
configuration by reversing the bias on the Input Reference, with the power supply return
connected to the reference. The inputs will then go to ground (LOW), and at 24V (HIGH) when
the switch is closed.
Input reference
Input 2 (Jog +)
Input 3 (Jog -)
Input 4 (G0)
LMD
Jog +
Jog -
G0
+5 to 24 VDC
+
–
Refer to the LMD MCode or the appropriate fieldbus manual for full setup and configuration
details for the inputs.
Input #
Function
Switch State
MCode Setup String
(Is=[in #],[func],[active])
Notes
2
JOG +
normally open
IS=2, 7, 0
Set IN 2 as + JOG, active when low (switch closed)
3
JOG -
normally open
IS=3, 8, 0
Set IN 3 as – JOG, active when low (switch closed)
4
G0
normally closed
IS=4, 4, 1
Set IN 4 as G0, active when high (switch open)
NPN Sensors in a Sinking Home/Limit ± Configuration
A common configuration is to have two sensors which define the PLUS and MINUS limits of
travel, and a third to home the axis. The following illustrates three NPN sensors connected to
the LMD inputs 2 - 4 in that configuration.
Input reference
Input 2 (LIMIT +)
Input 3 (LIMIIT -)
Input 4 (HOME)
LMD
+5 to 24 VDC
+
–
(brown) +
(black) signal
(blue) −
(brown) +
(black) signal
(blue) −
(brown) +
(black) signal
(blue) −
NPN sensors*
*wire colors shown
are typical for sensors
