First Time Operation; Figure 3.5 Typical Display - Michell Instruments Pura User Manual

Pura Online Hygrometer User's Manual
3.5

First Time Operation

Prior to operation, the instrument must be connected to the correct electrical power supply and the relevant
analog and alarm outputs connected to external systems as required and as described above.
To commence operation, proceed as follows:
1. Switch on the power supply to the instrument. The instrument display will now
come on, typically showing the default parameters and units as detailed in
Figure 3.5.
2. Check that the gas sample fl ow rate through the sample block or the pipeline in
which the transmitter is located is within the operational limits:
1 to 10 Nl/min (2.1 to 21.2 scfh) (5 Nl/min (10.6 scfh) optimum)
3. Adjust any external fl ow control valves, located in the gas sample input line to
the instrument, to achieve the required fl ow rate.
The instrument is now operational and after a few seconds, in which all the segments of the display are tested,
the process indicator will display the measured dew-point temperature as a steady reading within the range
-120 to -40ºCdp (-184 to -40ºFdp), depending upon how the instrument has been set-up. The default setting
is degrees Celsius.
In the absence of any error indications the instrument will now be operational using the default parameters,
typically as shown in Figure 3.5 .
If the display is fl ashing, a fault condition exists.
The following operational error conditions may be encountered:
• ' If the display is alternately fl ashing (e.g.) '
ErrL'
indicates that the measured dew point is outside the lower operational limit
(-120ºCdp ) and the numeric section of the display gives an indication of the
actual measured reading.
• If the display is alternately fl ashing '
to read temperature in ºF), this could be an indication that the input current
loop to the process indicator is open or that there may be a transmitter fault.
Check that the transmitter is wired correctly as detailed in Section 4.1.
• ' If the display is alternately fl ashing (e.g.) '
ErrH'
indicates that the measured dew point is outside the upper operational limit
(-40ºCdp) and the numeric section of the display gives an indication of the
actual measured reading.
97303 Issue 1.2, March 2016
Pura Online
Figure 3.5 Typical display
ErrL'
Hygrometer
and '
ErrL'
and ' , (or '
-154.9' -199.9'
and '
ErrH'
16
, this
-120.3'
if set-up
, this
-39.9'
Michell Instruments