Doc #: L-2600-1023 Page 37 Rev. 02
3.3.3.2 Description
The “Description” is a helpful label which aids the operator in identifying which sensor is tied to a
particular input and what that input is monitoring. This is of particular value if many die protection
inputs are used. Since the "Channel Type" labels are by necessity general in nature, an input description
can be used to give more specific information to the operator. For example, suppose two separate
sensors are being used to check for two different pilot holes in the part. The die protection inputs which
these sensors are wired to would both be programmed as “Cyclic” inputs to check proper operation of
the sensor (pilot hole both present and absent at different points in the stroke). In this application it
would be helpful to specify a description for each input such as "Pilot Hole Left" and "Pilot Hole Right”
so that if a failure occurred the operator would know immediately which hole was not seen. When the
“Description” field is touched, a list of available names that can be selected is displayed. This list is
configured by the user as explained in Section 4.6 on page 61.
3.3.3.3 Input Type
All channel logic types can have either “Normally Off” or “Normally On” input types. A sensor will
switch from its normal state when the event that it is monitoring takes place. For example, if a
“Normally Off” sensor is being used for stripper plate detection, the sensor will turn “On” when the
stripper plate is detected. The majority of sensors used will be “Normally Off” input type.
3.3.3.4 Sensor Output
The “Sensor Output” can be set to either “NPN (Sink)” or “PNP (Source)”. Sensors used with the die
protection system should have a maximum off-state leakage current no greater than 1.9 milliamps. The
maximum on-state voltage drop of the sensor should be no greater than 12 volts. These parameters are
usually specified in the datasheet or catalog page for the sensor.
When “Sensor Output” is set to “NPN (Sink)”, the die protection input will be pulled up to about 22
volts with a resistor. NPN sensors (also called “sinking” or “current sinking” sensors) connected to the
input “pull it down” to something close to 0 volts when the sensor turns “On”. In the case of an
inductive proximity sensor, the sensor turns “On” when metal is sensed, but any sensor that in effect
switches the input to ground when “On” should use this input type. For instance, a mechanical limit
switch that is tied between ground and the input would use a “Sensor Type” of “NPN (Sink)”. This
would also be applied to a whisker probe that is grounded when it touches its target.
When “Sensor Output” is set to “PNP (Source)”, the die protection input will be pulled down to 0 volts
with a resistor. PNP sensors (also called “sourcing” or “current sourcing” sensors) connected to the
input “pull it up” to something close to 24 volts when the sensor turns “On”. In the case of an inductive
proximity sensor, the sensor turns “On” when metal is sensed, but any sensor that in effect switches the
input to 24 volts when “On” should use this input type. For instance, a mechanical limit switch that is
tied between 24 volts and the input would use a “Sensor Type” of “PNP (Source)”.
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