MTS Series 793 - Manual (Page 289)

How to enable limit detectors
By default, limit detectors are initially disabled. So even if you enable a limit detector at its initial setting (±130%
of its range value), it still will not work because the sensor conditioner’s hardware will saturate before attaining
±130% of the current range.
To allow a limit detector to work in a given range, you must:
• Change its limit value so that it falls within ±100% of its range, and
• Enable it (change its selected action from “Disable” to the desired action)
To make a limit detector work, you must change its initial setting so that it is within ±100% of the selected
range (as shown).
Be aware of detector settings when changing ranges
When you go from a larger range to a smaller range, limit detector do not automatically change, so they may
not apply to your new range.
When this occurs, the controller will display the following message:
The range selected for signal -signal name- has left one or more of the signal's detectors outside of the new
range.
Please verify that the detectors (limit and error) associated with this signal are adjusted as necessary.
For example, suppose you have a configuration in which Range 1 spans ±10 kN, with limits set at 9 kN and
-5 kN, as shown below in the figure to the left. Both limits are viable for Range 1.
Next, suppose you select Range 2, which spans ±6 kN, as shown below in the figure to the right. In this case,
the 9 kN limit would not be applicable to Range 2, and the application would display the message. However,
the -5 kN limit still falls within the span of Range 2.
MTS Series 793 Control Software 289
Station Setup