General Description; Modes Of Operation - Sentry Sample Sequencer 5 Installation, Operation And Maintenance Manual

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Sentry Equipment Corp | Sample Sequencer 5

4 GENERAL DESCRIPTION

The Sentry Sample Sequencer is a microprocessor-based instrument capable of electronically
switching up to eight sample streams one at a time to an analyzer and of providing signals to
recorders. If a total of eight sample streams are not needed for one process, the remaining points
may be assigned to additional analyzers, up to four in total. A Sentry manifold sampling valve
specially designed to obtain optimum representative samples is available for sample stream
switching with the Sample Sequencer. The Sample Sequencer reduces the number of required
analyzers while maintaining equivalent data accuracy. Reliable sample analysis comparison is
obtained by using a Sample Sequencer with one dedicated analyzer. In addition, significant
operating cost savings are obtained by not having to install, maintain, and service multiple
analyzers.
The Sample Sequencer is capable of operating in the continuous mode for continuous analyzers
or in the batch mode for batch analyzers. In addition, the Sample Sequencer is capable of
measuring the analyzer analog output signal and converting the analog signal to digital data to be
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sent out using MODBUS TCP/IP or Embedded web using the Ethernet communication port.
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Using the MODBUS capability, one can connect to a PC or system network via the Ethernet
cable to one or more Sequencers for remote monitoring, control, and data acquisition.
Track and Hold outputs are available to provide independent outputs for each sample point. Digital
outputs are also available to provide channel number indication as well as replicating analyzer
alarms.
Figures 1-3 illustrate a typical system arrangement for sample stream switching with the Sample
Sequencer. Customer-supplied equipment is shown for clarification.
4.1

Modes of Operation

The Sample Sequencer has two programmable modes of operation:
4.1.1 BATCH
Used for analyzers that take a sample "bite" (or batch), produce an analytical result, and then
provide a contact signal output, in typically 1-20 minutes.
4.1.2 CONTINUOUS
Used for analyzers that continuously produce an analytical result.
NOTE
If using the Sample Sequencer with a Hach analyzer, see Appendix B.
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