Appendix 3.2 Stream Multiplex Mode - Hach BioTector B7000 User Manual

Appendix 3.2
In Stream Multiplex Mode, one channel is dedicated to periodically change its value in steps to indicate the
sample stream information and the rest of the channels output appropriate stream reaction results. The output
channel, which indicates the reaction result stream information is called "Stream Identification (ID)" channel.
The output channels, which output the reaction results are called "Reaction Result" channels.
Unlike the Direct Mode, where output channels are totally independent from each other, in the Stream
Multiplex Mode, the meaning of reaction result channels is conditioned by the stream identification channel. In
addition, in Stream Multiplex Mode, all output channels change over time in a periodical manner. The whole
Stream Multiplex Mode output sequence can be described as follows:
1. 4-20mA READ output is deactivated, Stream ID channel is set to CHANGE value
2. wait programmed time delay (Signal Hold Time, default value 10s)
3. reaction results channels are updated with N
4. Stream ID channel is set to indicate N
5. wait 1 second time delay
6. 4-20mA READ output is activated
7. wait programmed time delay (Signal Hold Time, default value 10s)
8. do the steps 1-7 for all analyzed streams, if all carried out then continue with step 9.
9. 4-20mA READ output is deactivated
10. Stream ID channel is set to CHANGE value
11. wait for a new result or programmed time (Update Period) and start with step 1.
An example of Stream Multiplex sequence is shown in figure A3.2, where the system outputs TIC, TOC, TN
reaction results for streams 1, 2 and 3.
Figure A3.2 An example of BioTector 4-20mA output signals in Stream Multiplex Mode
Stream Multiplex Mode
th
stream valve
th
stream valve results
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