Hach BioTector B7000 User Manual page 160

The operation of 4-20mA READ signal is demonstrated in figure A3.2 above. Note that the 4-20mA READ
signal is always activated 1 second after changes on Stream ID and all reaction result channels. This function
allows the channels to stabilize their values. When this type of synchronization is used, the user device has to
sample the 4-20mA READ signal and search for a condition when this signal is activated before reading the
Stream ID and reaction results channels.
Irrespective to used synchronization mechanism, if the Stream ID channel is unstable or set to CHANGE level
or 4-20mA READ signal is deactivated, the values of reaction result channels will not be defined and will
usually be set to the latest output value.
An example of connection between the user device and the BioTector configured in Stream Multiplex Mode, is
shown in figure A3.3, where the 4-20mA READ signal is used for synchronization.
Figure A3.3 BioTector 4-20mA output signals in Stream Multiplex Mode
BioTector
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 6
4-20mA READ relay
A section of 4-20mA Program menu below shows the BioTector configuration in Stream Multiplex Mode,
which corresponds to the example output signals given in figure A3.2 above. As can be seen, the reaction
result channels are programmed to output TIC, TOC and TN components. Note that output 4-20mA channels
definition has been split between CHANNEL X and OUTPUT X menu parameters. The reason is the fact that
in this mode, the menu CHANNEL X parameters describe function of physical 4-20mA output channels and
menu OUTPUT X parameters determine what will be outputted on the physical channels.
4 - 2 0 m A P R O G R A M
1 < O U T P U T
2 C H A N N E L
3 C H A N N E L
4 C H A N N E L
5 C H A N N E L
6 C H A N N E L
7 C H A N N E L
8 C H A N N E L
9 O U T P U T
1 0 S I G N A L
1 1 S I G N A L
1 2 F A U L T L E V E L
1 3 O U T P U T
▼
Stream Multiplex
STREAM ID
INSTANTANEOUS TIC
INSTANTANEOUS TOC
INSTANTANEOUS TN
M O D E S T R E A M
1 S T R E A M
2 T I C
3 T O C
4 T N
5 - - -
6 - - -
7 - - -
P E R I O D 6 0 0 s
H O L D T I M E
F A U L T Y E S
1 . 0 m A
< 4 m A
0 9 : 1 7 : 2 8 1 2 - 0 9 - 0 2
M U X
I D
, I N S T
, I N S T
, I N S T
1 0 s
0 %
User Device
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