Applied Motion 7080i - Manual (Page 10)

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Limit Switches
The 7080i has two limit switch inputs, LIMIT CW and LIMIT CCW. By connecting
switches or sensors that are triggered by the motion of the motor or load, you can
force the 7080i to operate within certain limits. This is useful if a program error
could cause damage to your system by traveling too far.
The limit inputs are optically isolated. This allows you to choose a voltage for your
limit circuits of 5 to 24 volts DC. It also allows you to have long wires on limit
sensors that may be far from the 7080i with less risk of introducing noise to the
7080i. The schematic diagram of the limit input circuit is shown below.
If you want to operate the limit switch circuits at 24 volts, you must
add 1000 ohms in series with each limit switch. For 5 - 12V operation,
no external resistance is required.
If the sensor output goes high at the limit, choose the program option "closed." If
the output is low at the limit, select "open."
The current through the 7080i limit switch inputs must not exceed 20
mA. If your limit sensor power supply voltage is between 12 and 24
volts DC, add a 1000 ohm resistor in series with the sensor output. Do
not use voltages higher than 24 VDC.
If the sensor output goes low at the limit, select the option "closed." 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:
Wiring a Limit Switch
You can use normally open or normally closed limit switches. Either way, wire
them as shown here.
Limit Sensors
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 this:
Wiring for Sourcing Output
Wiring for Sinking or Open Collector Output
7080i
CW LIMIT-
+
DC
Power
Supply
–
Limit
Sensor
CW LIMIT+
output
+
–
7080i
Controller
Chip
1K
4.7K
+5V +5V
3
4
1
2
CW LIMIT+
CW LIMIT–
CCW LIMIT+
CCW LIMIT–
TLP621 or
NEC PS2501
inside 7080i
7080i
CCW LIMIT+
CCW LIMIT-
CW LIMIT-
+
5-12
VDC
SUPPLY
-
CW LIMIT+
7080i
LIMIT-
+
DC
Power
Supply
–
Proximity
Sensor
LIMIT+
output
+
–