OAFE-2000
IO&M Manual
Paragon Controls Incorporated
25
Revision Level 000
If Lockdown is set too low
The MTSE may show flow when the air handling unit or system is off; increase Lockdown.
Adjustments should be small as it may take the duration of the lockdown delay and the rolling
average in the system filters to catch up before flow is locked to zero.
If Lockdown is set too high
1) The MTSE may show no flow on the Main Screen while the system is running. Navigate to the
Sensor Data Page and determine whether the individual sensors show flow and pressure; if so,
decrease Lockdown a little at a time until flow is displayed on the main screen. Adjustments
should be small as it may take the duration of the lockdown delay and the rolling average in the
system filters to catch up before flow begins to be displayed.
2) If Lockdown is set that is above a low flow alarm value, the system will enter into an alarm state
when the reading falls below the lockdown value after the set lockdown delay. For example,
with the following settings:
Operating Range at 10,000 cfm,
Lockdown set at 10%, which equals 1,000 cfm
Low flow alarm set at 500 cfm
The MTSE will report zero flow and therefore enter a low flow alarm when the measured
flowrate falls below 1,000 cfm for the duration of the lockdown delay. Therefore, a low flow
alarm will be triggered at about 1,000 cfm, not the desired 500 cfm. If the user wishes to read
flowrates down to and alarm at flows below 500 cfm in the above example, decrease the
lockdown percentage below the alarm value (
≤
5%).
Lockdown Delay
The Lockdown Delay allows the user to enter a lockdown time delay from 0 to 999 seconds that will
delay the display and output locking to zero from occurring until the process value has remained below
the lockdown value for that duration. Lockdown Delay is useful when systems are operating very close
to the lockdown value but because of project limitations the lockdown value cannot be reduced; when
the system flows fluctuate momentarily below the lockdown value the system will still show flow until
this delay time is exceeded. The Lockdown Delay will be global across all Systems and 2
nd
OA.
The
default Lockdown Delay value is 10 seconds
.
5.2.8. Units and Precision
Selecting this menu allows the user to set the measurement type (pressure, velocity, or flow), the
engineering units depending on the measurement type selected, and the number of significant figures.
Shown below is the Units and Precision page. Navigate to this menu from the Main Screen by pressing
Setup » 8. Units and Precision
.
