Doc #: L-2600-1023 Page 24 Rev. 02
3.3.1.1 Static
Static inputs are used for sensors that monitor
events that are independent of the production
machine cycle. Examples are sensors
monitoring end of stock and stock buckling.
If the input is programmed with a channel
type of “Static” and an input type of
“Normally Off”, the input should NOT be
“On” under normal operation. In this case
when the input switches “On”, a stop will be
issued. If the input is programmed with a
channel type of “Static” and an input type of
“Normally On”, the input should be “On”
under normal operation. In this case when
the input switches “Off”, a stop will be
issued.
An example of the use of a Static Normally
Off input is stock buckling detection, as
shown in “a” of Figure 9. The stock to be
fabricated is placed between a dual probe in
the normal position. The probe remains “Off” (ungrounded) unless the stock buckles upward or
downward far enough to touch the upper or lower portion of the probe, turning “On” (grounding) the
normally open input, causing a fault.
An example of the use of a Normally On
input is an end of stock sensor, as shown in
Figure 10. A probe is mounted so that it is
“On” (grounded) by the stock being fed into
the production machine. When the end of
stock is reached, the probe will no longer
contact the stock, turning “Off” the input and
causing a fault.
An additional feature of Static type inputs is a
“Delay Time” parameter which is set by the
operator. A programmed time of zero forces
ordinary operation of the static input as
described above, i.e., if the input is not in the
'normal' state, a fault will occur immediately.
However, if a value other than zero is
programmed the input is allowed to change
from the normal state for the length of time
programmed without a fault occurring. If the
input does not return to the normal state before the time expires, a fault is generated. This allows the
operator to avoid nuisance faults from sensors that 'bounce' open or closed momentarily. The delay time
can range from 0 to 65535 milliseconds (65.535 seconds) in 1 millisecond increments.
Dual Probe Extends Over Stock
To Detect Stock Buckle
Die Stock Guide
Die Stock Guide
Feed
Feed
To Die Protection Input
Programmed For
Static Normally Off
To Die Protection Input
Programmed For
Static Normally Off
a) Dual Normally Open Probe Used To Detect Stock Buckle
b) Lever Arm Held Open By Stock Detects End Of Stock
Figure 9: Static Normally Off Example
Die Stock Guide
Feed
To Die Protection Input Programmed
For Static Normally On
a) Probe Provides Normally Closed Input To Monitor End Of Stock
b) Limit Switch Provides Normally Closed Input To Monitor End Of Stock
Die Stock Guide
Feed
To Die Protection Input Programmed
For Static Normally On
Normally Open Switch
Held Closed By Stock
Spring
Probe
Figure 10: Static Normally On Example
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