Campbell Scientific EC155 CO2 and H2O Closed-Path Gas Analyzer and EC100 Electronics with Optional CSAT3A 3D Sonic Anemometer - Manual (Page 29)

EC155 CO
2
and H
2
O Closed-Path Gas Analyzer
7.2.5 RS-485 Baud Rate
If the unprompted output mode is set to RS-485, this parameter determines the
baud rate. Otherwise this setting is not used. The RS-485 baud rate defaults to
115200 bps, although the user may enter another value.
7.2.6 Analog Output
The EC100 has two analog outputs for CO
2
and H
2
O molar mixing ratios (see
Section 8.3, Analog Outputs for more information). These outputs may be
enabled/disabled with this setting. The default is for analog output to be
disabled.
7.2.7 ECMon Update Rate
This setting determines the rate at which data are sent over the USB connection
to the PC while running ECMon. The default setting of 10 Hz should be
adequate in most situations.
7.2.8 Temperature Sensor
The EC155 measures the temperature of the sample cell block with a
thermocouple embedded in the block. With the Auto-Select default setting,
the EC100 will automatically detect that an EC155 is connected to the
electronics and will report temperature measurements from the sample cell
thermocouple.
To diagnose problems with the temperature measurement, a fixed temperature
value may be used, or the temperature sensor may be selected manually.
7.2.9 Fixed Temperature Value
If the Temperature Sensor setting is None, the EC155 will use the value of
this setting for the sample-cell temperature. This mode is intended for
troubleshooting only. In normal operation, the Temperature Sensor is set to
Auto-Select, and this setting is not used.
7.2.10 Pressure Sensor
This setting determines which pressure sensor will be used to measure the
barometric pressure. The EC100 always includes the EC100 basic barometer,
but it may be ordered with the optional EC100 enhanced barometer. This
setting is factory defaulted to the enhanced barometer if it is ordered, and to the
basic barometer otherwise.
There are two other possible settings for the Pressure Sensor. First, the user
may provide his or her own pressure sensor. In this case the setting should be
changed to User Supplied, with the appropriate values for gain and offset
entered (see below). This option may be used if the EC155 sample cell is to be
used outside the range of the differential pressure sensor (see Section 7.2.11)
For this mode the user-supplied pressure sensor must be plumbed to the EC155
sample cell, and the Differential Pressure sensor setting should be disabled.
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