Connecting limit switches – Applied Motion Si2035 User Manual

Page 11

Si2035 Hardware Manual

Connecting Limit Switches

The CWLIMIT and CCWLIMIT inputs are used for connecting end of travel sensors. These
inputs are differential, which allows you to use signals that are sinking (NPN), sourcing
(PNP) or differential (line driver). By connecting switches or sensors that are triggered by
the motion of the motor or load, you can force the motor to operate within certain limits.
This is useful if a program or operator error could cause damage to your system by travel-
ing too far.

The limit inputs are optically isolated. This allows you to choose a voltage for your limit
circuits of 12 to 24 volts DC. This also allows you to have long wires on limit sensors that
may be far from the drive with less risk of introducing noise to the drive electronics. The
schematic diagram of the limit switch input circuit is shown below.

Si2035 Limit Input diagram

Wiring a Mechanical Limit Switch
You can use normally open or normally closed limit
switches. Either way, wire them as shown here.

Wiring a Limit Sensor
Some systems use active limit sensors that
produce a voltage output rather than a switch or
relay closure. These devices must be wired
differently than switches.

If your sensor has an open collector output or a
sinking output, wire it like the example left:

If the sensor output goes low at the limit, select the option “closed” (in the software). If
the output is open, or high voltage, choose “open”.

Other sensors have sourcing outputs. That means that current can flow out of the sensor
output, but not into it. In that case, wire the
sensor this way:

2200

inside Si2035

CWLIM+

CWLIM-

CCWLIM-

CCWLIM+

Si2035

12-24

VDC

SUPPLY

CW LIMIT-

CCW LIMIT+

CW LIMIT+

CCW LIMIT-

Si2035

Power

Supply

–

Limit

Sensor

output

–

LIMIT+

LIMIT-

Si2035

Power

Supply

–

Proximity

Sensor

output

–

LIMIT+

LIMIT-