Rockwell Automation T8442 Trusted TMR Speed Monitor - Manual (Page 27)

Trusted
TM
Module T8442
Issue 8 Apr 10 PD-T8442 27
Consider the following example:
A channel has been configured with an over-acceleration trip threshold of 1000 RPM/second and an
over-acceleration deadband value of 950 RPM/second.
The channel will trip when the acceleration reaches or exceeds 1000 RPM/second and will not revert to
the non-tripped state until the acceleration falls to 50 RPM/second or less.
The configuration will appear in the speed monitor configuration template as: OADB
3.1.8. Speed Discrepancy Threshold
This field can be set for each input group.
The input value configures the maximum speed discrepancy in RPM that can be tolerated between the
three channels within a group.
The range of values that can be used for this field are 0 to 10000. The value must be less than or
equal to the Over Speed Limit. The default value is zero. The configured value may be adjusted when
the group is at zero speed.
If the speed discrepancy between channels within the same group exceeds this configured value, for a
period exceeding the configured Discrepancy Duration Limit (see3.1.10), then the discrepant channel
is declared faulty.
Speed discrepancy detection is disabled for input channels operating below the configured Minimum
Speed (see 3.1.2) or configured with zero teeth (see 3.1.1).
The configuration will appear in the speed monitor configuration template as:
SPEED_D =
3.1.9. Acceleration Discrepancy Threshold
This field can be set for each input group.
The input value configures the maximum acceleration discrepancy in RPM/second that can be
tolerated between the three channels within a group.
The range of values that can be used for this field are 0 to 10000. The value must be less than or
equal to the Over Acceleration Limit. The default value is zero. The configured value may be adjusted
when the group is at zero speed.
If the acceleration discrepancy between channels within the same group exceeds this configured
value, for a period exceeding the configured Discrepancy Duration Limit (see 3.1.10), then the
discrepant channel is declared faulty.
Acceleration discrepancy detection is disabled for input channels operating below the configured
Minimum Speed (see 3.1.2) or configured with zero teeth (see 3.1.1).
The configuration will appear in the speed monitor configuration template as:
ACC_D =