Rockwell Automation T8442 Trusted TMR Speed Monitor - Manual (Page 28)

Trusted
TM
Module T8442
Issue 8 Apr 10 PD-T8442 28
3.1.10. Discrepancy Duration Limit
This field can be set for each input group.
The input value configures the time limit in milliseconds, after which discrepant channels within a group
are declared faulty.
The range of values that can be used for this field are 0 to 65535. The default value is zero. The
configured value may be adjusted when the group is at zero speed. A value of 0 will disable both
speed and acceleration discrepancy latching (i.e. discrepant channels will not be declared as faults).
The discrepancy timer automatically resets when a previously discrepant channel returns below the
discrepancy threshold.
The configuration will appear in the speed monitor configuration template as:
D_DUR =
3.1.11. Acceleration Filter
This field can be set for each input group.
The input value configures the number of speed samples that are averaged together to produce an
acceleration value. Larger values result in less acceleration noise, but greater response time.
The range of values that can be used for this field are from 0 to 40 (excluding 1 which is not
accepted). The default value is 16.
A value of 0 will yield the default filter value, which is 16 samples. The boxcar averaging length is
equal to num_samples-1 multiplied by the sample time. The sample time is 6 milliseconds.
The configuration will appear in the speed monitor configuration template as:
ACC_F =
3.1.12. Acceleration Filter Default Checkbox
This checkbox can be set for each input group.
Setting this checkbox to the ticked state forces the Acceleration Filter to its default value.
3.1.13. Output Non-Latching Checkbox
This checkbox can be set for each output within a group.
Setting this checkbox to the ticked state will configure the associated output as non-latching.
If the checkbox is clear the associated output will be configured as latching.
In non-latching mode an output trip condition will only persist while the speed or acceleration value for
the group exceeds the configured threshold, taking into account the configured deadband.
In latching mode (default) an output trip condition will persist until the associated output is explicitly
cleared through the application interface or by the auto-reset function (see 3.1.14). A latched output
trip cannot be cleared through the application interface if the input trip condition still persists.
The default mode of operation is latching outputs.
The configuration will appear in the speed monitor configuration template as:
NO_LATCH <0|1>
Channel 0 is for the over-speed output, and channel 1 is for the over-acceleration output within a
group.
Mode 0 is latching and 1 is non-latching.