PP Systems CIRAS-2 - Customized Operation of CIRAS-2 at Humidity Levels above Ambient; CIRAS-2 Time; Analog Outputs

System Setup and Operation
CIRAS-2 Operator's Manual Version 2.04
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from wind and sudden pressure changes. Create a “smoothing volume” such as a large plastic container
or sealed plastic bag and place the open end of the AIR IN gas line inside the smoothing volume. Finally,
remember to leave the CO
2
holder/regulator assembly in place in CIRAS-2 either with no cartridge or with
an exhausted CO
2
cartridge.
Customized Operation of CIRAS-2 at Humidity Levels Above Ambient
If you desire to work at humidity levels above ambient, you can do so as follows:
Ensure that Absorber Column 3 (as labelled on the bottom of CIRAS-2) is filled with new soda lime that
will humidify the air. Next, carefully remove and cover the water vapor equilibrator with clear plastic wrap
so it is isolated from ambient. Replace the equilibrator in the manifold.
Or
Carefully remove and cover the water vapor equilibrator with moist filter paper and reattach it to the
manifold. In very hot dry conditions you can also cover the filter paper in clear plastic wrap to minimize
evaporation.
CIRAS-2 Time
CIRAS-2 can be set to match the exact date and time of the PC (integral PC or Lab PC) or to a different
date and time if required. To match the values to the PC, click on Set Values to System Time.
Otherwise, a different date and time can be set as required. Once set, press OK/Apply to accept the
settings or Cancel to return to the Settings dialog.
Please note that setting the CIRAS-2 Clock takes a few seconds. If the software detects that the CIRAS-2
clock differs by more than 1 hour from the UI or Pencentra clock, the CIRAS-2 time will be set to the UI or
Pencentra time automatically. This option is only available when CIRAS-2 is connected.
Analog Outputs
The 8 pin LEMO type socket labelled SIG OUT on the CIRAS-2 is used for the analog outputs. All outputs
have a maximum voltage of 5.0 V from a source impedance of about 60 ohms. Therefore, if external
resistors are used to drop the voltage, it is recommended that they exceed 10 Kohms in total.