Sentry Sample Sequencer 6 Installation, Operation & Maintenance Manual page 28

analyzer outputs an end-of-batch signal to the Sample Sequencer 6. If the sequencer does not receive an end-of-batch
signal, it does not advance to the next sample. Upon receiving an end-of-batch signal from the analyzer, the sequencer
reads the analyzer value, updates the Track and Hold output, and closes the point identifi cation relay.
 NOTE
The updated Track and Hold output and point identifi cation relay are for the previous sample point . The open valve number
never matches the closed relay point identifi cation in Batch mode .
The following considerations should be made when determining the timing for your Batch mode system:
ƒ End-of-Batch: The sequencer receives this signal when the analysis is completed and the analyzer is ready to begin
a new analysis.
ƒ Analyzer Alarm: The sequencer receives this signal when the analyzer is in alarm, such as a loss of sample fl ow
condition. Once the analyzer alarm signal is received, the sequencer starts the sample timer and replicates the
analyzer alarm for use by external recorders and control systems.
ƒ Sample Time: The sample time in Batch mode is a timeout timer that operates only when the analyzer is in alarm.
While in alarm, if an end-of-batch signal is not received before the sample time expires, the sequencer closes the
current sample point and proceeds with the next sample point. Since the analyzer alarm input may serve to indicate
more than a loss of sample fl ow, the sample time should be set to give the analyzer suffi cient time to attempt to
complete an analysis and output an end-of-batch indication.
Figure 11. Batch Mode Timing Diagram
28 Sentry Equipment Corp