SHIMPO 933 - Manual (Page 22)

22
Configuring For Devices With Contacts
Edit the current configuration parameters by opening the configuration dialog. See
Editing The Configuration, above, for details. Select the Contacts tab at the top of the
dialog. Set the Contact Type to the type of switch to be tested, Normally Open (NO) or
Normally Closed (NC) (Figure 11). This will establish the state of the contact when the
air cylinder is in the up (retracted) position.
Check or uncheck the Test Down Stroke and Test Up Stroke check boxes according to
the requirements of the switch. At least one of these check boxes must be checked. If
neither are checked, no contact testing is performed and there cannot be any test
failures. This is the same as setting up a no contact configuration. If bounce testing is to
be performed, check the appropriate up/down check boxes. Note that bounce can only
be tested if the resistance is tested in the same direction.
Set the Transition Thresholds by clicking or pressing and holding the adjacent spin
buttons. If bounce is not being tested, the upper and lower thresholds should both be set
to approximately 50%. If bounce is tested, set the thresholds according to the
requirements of your switch and the ASTM Designation F1661-96 specification. The
lower threshold must be less than or equal to the upper threshold.
Set the Minimum and Maximum Resistance for both the up and down strokes. The
minimum values can be 0. The maximum values can be very large. The word “open”
can also be used to set a tolerance limit for an open circuit. Note that for each stroke
direction the Min Resistance value must be less than or equal to the Max Resistance
value. Because of the granular resolution of the resistance measurement method, some
numeric values entered must be re-adjusted when the OK button gets pressed. When a
value is modified, the user is warned and a dialog box pops up asking if the user wants
to review the changes. By pressing yes, the user is again presented with the
configuration data dialog showing the altered values.
Set the up and down stroke bounce limits. The minimum value is 0, the maximum is 0.1
seconds. If bounce isn’t being tested, just enter a valid value.
Choose the Test Time tab. Set the maximum up and down stroke time based on the test
criteria. The cylinder air pressure, flow rates and stroke length all affect the test time.
Also required is extra time for the LCTS to dwell at the motion extremes. The user must
determine the up and down stroke times based on the item tested. The Maximum stroke
times must be limit to a range of 0.025 to 5.000 seconds each. The Minimum stroke
times are limited to the same range and, by definition, must be less than or equal to the
same direction Maximum stroke time.
The Minimum stroke times are measured from the first transition of the electrical contact.
The Maximum Stroke times are measured from the command to the air value that drives
the air cylinder. The Minimum stroke times should be based on the characteristics of the
switch contact as it stabilizes. Note that the bounce test measurement will never exceed
the Minimum stroke time. Be certain that the Maximum Bounce Tolerance is less than
the Minimum stroke test time. See Section 3 for further discussion.