MSA Senscient ELDS 1000 series, Operating Manual

Page: 121 / 184

Problem Solving
Senscient ELDS™
Rev 15 121
GB
7.2.1 Receiver Diagnostics Screen
RX Unit
The RX Unit box contains information about the Type (Open Path or Cross Duct), Gas(es),
Measurement Range(s) and Hazardous Area Certification of the Receiver with which SITE is
communicating.
Gas Level
The Gas Level boxes contain the latest readings for each gas that the ELDS gas detector is being
used to detect. Typically, these readings are updated every second, although this may vary
depending upon the gas detector variant (Cross Duct ELDS systems update the gas readings on
their outputs every 0.25 seconds); and the quality of the communication link. In addition to the
latest readings, each Gas Level box displays the analog current that is being output on the
corresponding 4-20mA output, which current provides an indication of the latest gas reading or of
the status of the gas detector.
The measurement units and range are displayed in the bottom left corner of each Gas Level box.
Signal Level
Under normal circumstances, the Signal Level box displays the signal level(s) being received from
each laser of the ELDS Transmitter opposite. Depending upon the path-length, alignment and
prevailing visibility, the signal level(s) should be somewhere in the range 0.05 to 2,000. (NB: When
SITE is used to install and commission an ELDS system, it will perform a check that the signal
levels being received are reasonable for the path-length over which the system is being operated).
When there is a numeric value being displayed in the Signal Level box for the laser signal(s) being
received, this indicates that valid, workable signal(s) are being received and that the ELDS system
should be operating correctly as a gas detector.
Info.
The Info. Box contains information about the AGC Gain, Status and Time & Date of the Receiver
with which SITE is communicating.
The Gain is an indication of the level of signal gain being provided by the Receiver’s Automatic
Gain Control (AGC) amplifier. This gain level is described by the combination of two descriptors
which are (High or Low) gain, and a number between 0 and 18. The very lowest level of AGC gain
is 0 Low; whilst the very highest level of AGC gain is 18 High.