MTS Criterion 40 - Manual - Manual (Page 105)

Setting Crosshead Travel Limits
MTS Criterion ® Series 40 Product Manual
Operation 105
Setting Crosshead Travel Limits
There are two levels of crosshead limit stops that act to protect the crosshead
from traveling too far in either direction. The first-level stops are the upper and
lower limit stops that you manually set as described below. The second-level
limits are not user adjustable and act as a backup in case the first-level limits
malfunction.
The limit stops are not intended to end every test.
Repeated use of the limit stops in this way may cause excessive wear,
which can result in the limit stop failing to stop the crosshead.
Refer to the Warning below for more information on unexpected crosshead
motion. Proper end of test conditions can be set from the software.
Do not use limit stops to end a test.
Crosshead limit stops
Unexpected crosshead motion can occur during testing.
Failure to set the limit stops could cause injury from unexpected crosshead
motion, and cause possible damage to test fixtures.
Always set the limit stops before starting a test.
Note Set the crosshead limit stops after you establish the crosshead starting
position, but before you start the test.
The travel limit stops are two adjustable blocks mounted on the limit switch rod,
which is located inside the column of the machine. Limit stops have
thumbscrews that you tighten and release by hand, and you can move them to any
position on the limit rod. Position these stops just beyond the test parameters to
prevent crosshead over-travel. When the crosshead reaches the maximum pre-set
travel, the limit switch actuator contacts one of these stops. Contact between the
limit actuator and the limit stop moves the limit switch rod and activates the limit
switches. This stops crosshead motion.
Setting the limit stops
To set the limit stops:
1. Ensure that the crosshead is stationary and that the test parameters are set.
2. Set the upper limit stop at a position just above the expected maximum
crosshead travel in the upward direction when tension testing, or just above
the test starting point when compression testing. Tighten the stop securely
on the limit rod.
CAUTION
WARNING
Criterion_product manual.book Page 105 Monday, July 28, 2014 3:52 PM