Sentry Sample Sequencer 6 - Operating Modes

26 Sentry Equipment Corp
ExComms Conguration
ExComms Conguration allows the user to change settings for the web interface. Note that the unit must be rebooted
for these changes to take eect.
Operating Modes
Continuous Mode
Continuous mode is for continuous output analyzers such as sodium, conductivity, pH, O
2
, some colorimetric, and many
others.
Timing considerations for Continuous mode
Figure 12 illustrates the timing diagram for Continuous mode. The following considerations should be made when
determining the timing for your system.
 Analyzer Alarm: An analyzer alarm immediately closes the active sample valve and opens the next sample valve.
That sample valve remains open until the analyzer alarm clears or one minute elapses. After one minute, the sample
sequencer opens the next sample valve. The sequencer continues trying to establish ow every minute until the
analyzer alarm clears.
 Calibration Hold: A calibration hold signal causes the sample sequencer to wait at the active sample with the valve
open. Once the calibration indication clears, the sequencer resumes operation, entering the Flush state for the
sample that was active before the calibration hold indication was received.
 Flush Time: After switching to a successive stream, the analyzer needs a settling time to stabilize to the new sample.
The analyzer analog output signal is ignored during this time. The necessary ush time depends on the valve
manifold design, sample line length from the manifold arrangement, sample velocity, and analyzer response time.
 Sample Time: Sample time is the time period during which a valid analyzer signal is read. Analog outputs are
updated and point identication relay contacts are closed during this time. The necessary sample time should be set
long enough to recognize stable readings and to provide recording devices time to capture the data.