1188 Instruction Man DS5000.doc Page 13 of 16
Remote signalling of an alarm condition is provided by two internal changeover relays that
trigger at the same time as the LED’s. These relays are none latching and automatic ally
shutoff whenever the alarm condition clears.
It is possible during normal running to review the Alarm trigger points and the current
transmitter temperature without interrupting the monitoring process. Whenever a review is
activated, the LCD displays the requested value for 3 seconds before returning to the normal
Dewpoint reading.
•
To review the AL 1 trigger point press the ‘
S
’ key for 2 seconds.
•
To review the AL 2 trigger point press the ‘
T
’ key for 2 seconds.
•
To review the transmitter temperature, press the ‘
12
’ key for 2 seconds.
11 Pressure Correction
When either ºC or ºF dewpoint units are selected, the display always shows the dewpoint at
the ‘Line Pressure’ entered in the ‘Set -up’ menu.
All calculations to other engineering units are made from the ‘Sensor Pressure’ entered in the
‘Set-up’ menu.
It is therefore critical that the correct pressures are entered in the ‘Set-up’ menu in order that
the displayed values are correct.
11.1 Examples
•
If a sensor is installed at atmospheric pressure and the instrument is required to
display line pressure dewpoint at 8 Barg;
LP (Line Pressure) should be entered as 8.0 and SP (Sensor Pressure) should
be entered as 0.0.
•
If a sensor is installed at line pressure (8.0Barg) and the instrument is required to
display atmospheric pressure dewpoint;
LP should be entered as 0.0 and SP should be entered as 8.0.
•
If the instrument is required to display dewpoint at the installed sensor pressure
then the LP and SP should be both the same and equal to the sensor pressure.
At 8Barg line pressure, both LP and SP should be entered as 8.0.
•
Where the instrument is required to display any other engineering unit, the LP
value is irrelevant but the installed sensor pressure should be entered.
12 Monitoring the System
The system is designed to operate continuously, with a minimum amount of operator input.
It is, however, advisable to inspect the sample loop periodically to ensure that the required
pressures and flows are being maintained.
