Hach ORBISPHERE 410 User Manual page 59

Inputs/Outputs Menu
Analog outputs
There are three analog outputs available. These outputs are configurable in terms of function, content,
and behavior through the instrument menus. Analog outputs are used to output a voltage or a current
which is a function (e.g. a linear characteristic) of a measurement: AOut = f (M). The analog outputs can
be typically connected to a PLC. Knowing the function (f), the PLC can compute the value of the
measurement.
Two types of instrument hardware are available:
•
•
Instrument
configuration
Standard event
indication
Extended event
indication
Analog output
Gas
concentration
Temperature
58
measurement board with current output (I = 0-20 mA or 4-20 mA).
measurement board with voltage output (U = 0-5 V).
•
•
Note: Features of the instrument with a voltage analog output are similar to
the 0-20 mA features.
For some events (sensor out, purge failure, etc.) the actual measurement is
not significant, but the PLC needs to know how the analog output behaves
in these cases. Two "Event indication modes" are available:
•
•
Refer to
The "Extended event indication" mode is only available when the 4-20 mA
output is selected. In this mode, the range between 0 mA and 4 mA is used
to indicate selected events. The events are defined using the channel
configuration option. Refer to
Note: The extended mode is not available for the voltage output versions of
the instrument.
Event output range
0-20 mA
20 mA
20 mA
Select analog output range of current:
4-20 mA or 0-20 mA
The 4-20 mA range (recommended) allows for an extended event
indication mode that can be selected and configured (default = standard
mode)
Standard mode (default)
Extended mode
Table 1 Standard event indication
Channel configuration on page
Table 1 Standard event indication
4-20 mA 0/5 V
•
•
20 mA 5 V
•
•
•
20 mA 5 V
•
below.
Event
Channel out
Sensor out
Thermal cut-off
Interfering gas error
Channel out
Sensor out
59.