Sentry Sample II Low Pressure Installation, Operation & Maintenance Manual page 13

Operation Screen
The operation screen is the main screen on the Sample Sentry II. This screen contains
information indicating the status of the system. While in Manual mode, the system is
controlled from the operation screen.
Figure 5. Operation Screen
I n
B l
S V 1
Figure 5 shows a typical operation screen for the Sample Sentry II. The top line displays
temperature and pressure data. The screen periodically refreshes to show a different
measurement. Only measurements that are enabled are displayed.
Line 4 displays the state of the three valves. Figure 5 currently shows valve SV1 open, SV2
closed, and the PRV partially open. If the PRV display was completely filled in, it would
indicate that the PRV was fully closed.
Line 2 displays the state of the system, including the total flow rate. The 7 possible states
are Manual, Start, Blowdown, Sample, Stop, Remote, and Clean.
Manual: While in manual mode, the system can be controlled with the keypad on the
front of the controller. Pressing the MENU key displays the Main Menu password screen.
To place the system in Automatic mode, press the ENTER key. Pressing the ESC key toggles
valves V1 and SV2 between open and closed. Holding the ▲ key opens the PRV, while
holding the ▼ key closes the PRV.
Start: The controller waits in the Start state until the inlet pressure is greater than the
programmed startup pressure. The only key that is functional while in the Start state is the
ENTER key. Pressing the ENTER key returns the system to Manual mode.
Blowdown: Flow to analyzers is stopped by closing SV2, forcing the entire sample to flow
to the grab sample. When the system is in Blowdown, the time remaining in Blowdown is
displayed on line 3. Pressing the ENTER key returns the system to Manual mode. Pressing
the ESC key advances the system to Sample.
Sample: The controller opens SV2, allowing flow to analyzers. Pressing the ENTER key
returns the system to Manual mode. Pressing the ESC key returns the system to Blowdown.
Stop: The Stop state occurs when the total flow falls below a shutdown set point and the
PRV is full open or if the pressure is lower than the shutdown pressure set point. During
the Stop state V1 is closed, the PRV is adjusted to its set point, and SV2 is closed. After
these valves are adjusted, the controller advances to Start if automatic startup is enabled
or Manual if disabled.
Remote: Remote indicates the system is being controlled remotely with the MODBUS
communications port. While in the Remote mode, the controller enters the Blowdown and
Sample states as determined from remote commands. Pressing the ENTER key returns the
system to Manual mode.
Sentry Sample Sentry II
l e t 1 5 0 0
o w d o w n
0 : 2 7 : 3 7
S V 2
P S I
1 4 0 7
P R V
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m i n
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