In the following, the recording of a limit value-based preventive activity is explained:
Assuming that object monitoring is to propose an activity when a limit value is exceeded (actual value greater than limit value), e.g. when the temperature of “Machine 1” exceeds a limit value, a time schedule must be assigned, e.g. for checking “Machine 1”, and the “Threshold / Range” info tab must be completed.
- First, it must be navigated to the technical object “Machine 1”.
- An object monitoring line is added and
- First the template code is selected,
- Then, the associated Inspection Time Schedule for the “Machine 1” is assigned.
By opening the Card view of the object monitoring line (clicking on “Process”, then “Card”), it is possible to define in the “Threshold/Range” info tab, under which conditions a maintenance appointment should be proposed, as the following variants are supported by MAIN-TOOL:
- Limit Value Overrun (actual value greater than limit value),
- Limit Value Underrun (actual value less than limit value),
- Limit Value Over- or Underrun (in the sense of „either or“),
- Exceeding a positive or negative deviation from a setpoint.
In the following chapters, all variants are explained by means of examples.
Threshold/Range Info Tab Setup - Limit Value Overrun
The following table shows the relevant field entries in the required order of entry from top to bottom to propose an activity when a limit value is exceeded:
| Field Name | Description / Information |
| Action by Value | Maximum Value |
| Maximum Threshold | Entry of a limit value, if exceeded (actual value greater than limit value), an activity should be proposed |
| Reference Value | Value Entry of the setpoint |
| Maximum Critical Value | Enables additional optional (not alternative) definition of a critical value, above which the activity should be proposed (no functional difference from the “Maximum Threshold”, the “Maximum Threshold” field must not be left empty, as this will be interpreted as an entry with value “zero”). |
Note:
- During entry, the values are checked for plausibility. If a value was entered incorrectly, it is recommended to first set the “Reference Value” to "zero" and then to correct the “Maximum Threshold” if necessary, as otherwise a check may prevent the correction.
Threshold/Range Info Tab Setup - Limit Value Underrun
The following table shows the relevant field entries in the required order of entry from top to bottom to propose an activity with the underrun of a limit value:
| Field Name | Description / Information |
| Action by Value | Minimum Value |
| Maximum Threshold | Entry of a value above the Reference Value required. Field must not be empty, otherwise it will be interpreted as „zero“ |
| Reference Value | Value Entry of the setpoint |
| Minimum Threshold | Entry of a limit value below which an activity is to be proposed |
| Minimum Critical Value |
Enables additional optional (not alternative) definition of a critical value, below which the activity should be proposed (no functional difference from the “Minimum Threshold”, the “Minimum Threshold” field must not be left empty, as this will be interpreted as an entry with value “zero”). |
Note:
During entry, the values are checked for plausibility. If a value was entered incorrectly, it is recommended to first set the “Reference Value” to "zero" and then to correct the “Maximum Threshold” if necessary, as otherwise a check may prevent the correction.
Threshold/Range Info Tab Setup - Limit Value Over- or Underrun
The following table shows the relevant field entries in the required order of entry from top to bottom to propose an activity with the Over- or Underrun of a limit value (“either or” Condition):
| Field Name | Description / Information |
| Action by Value | Both |
| Maximum Threshold | Entry of a limit value, if exceeded (actual value greater than limit value), an activity should be proposed |
| Reference Value | Value Entry of the setpoint |
| Minimum Threshold | Entry of a limit value below which an activity is to be proposed (actual value less than limit value) |
| Maximum Critical Value | Enables additional optional (not alternative) definition of a critical value, above which the activity should be proposed (no functional difference from the “Maximum Threshold”, the “Maximum Threshold” field must not be left empty, as this will be interpreted as an entry with value “zero”). |
| Minimum Critical Value | Enables additional optional (not alternative) definition of a critical value, below which the activity should be proposed (no functional difference from the “Minimum Threshold”, the “Minimum Threshold” field must not be left empty, as this will be interpreted as an entry with value “zero”). |
Threshold/Range Info Tab Setup - Negative or Positive Deviation
In addition to the functions already shown, MAIN-TOOL supports the consideration of the deviation from the reference value, if e.g. a humidity or temperature measured value increases or decreases disproportionately fast from posting to posting. The two fields "Maximum Negative Deviation" and "Maximum Positive Deviation" are available for this purpose. What was previously posted is compared with the new posting booking, the difference of both postings must not exceed the specified deviations, otherwise the activity is proposed.
| Field Name | Description / Information |
| Maximum Negative Deviation | Entry of a maximum negative deviation value below which an activity is to be proposed |
| Maximum Positive Deviation | Entry of a maximum positive deviation value above which an activity is to be proposed |
Note:
- Such definitions only make sense if the performance data are updated regularly, e.g. by means of an interface to a measurement data acquisition system.
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