Download Site Operators Manual - UK-Air

SITE OPERATORS MANUAL
8
AEAT/ENV/R2750
Data Logging And Data Transmission
Equipment
Two methods of data logging are used in the AURN. The analysers themselves either contain
data logging capabilities or, standalone loggers (which may be PCs) these are used to scan the
outputs of the analysers and record data. Both systems can be interrogated by the Management
Unit data collection systems.
The logger scans the analyser output approximately every 10 seconds and stores them as 15
minute averages in the logger memory.
The data logger is programmed to trigger the daily analyser autocalibrations using control signals
which drive relays to initiate zero and span measurement cycles. Status inputs to the logger from
analysers are used to monitor instrumental performance and detect error conditions.
The logger (or analyser) is connected through an RS232 serial interface to an autodial-autoanswer modem operating at a data transmission rate of up to 9600 baud. The modem is
connected, via the public telephone system, to the Managements Unit’s central computer which
automatically collects the logged data.
In the past chart recorders were used to provide a secondary data backup, however they are now
unsupported
8.1 Data Retrieval
The CMCU and use a commercially available data retrieval system to poll data from sites on an
hourly basis .
AEA
A41