Ametek Land 4750-PM, Руководство пользователя

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User Guide 5 - 12
Particulate Measurement System 4750-PM
5.5 Data Communication
There is no data logging capability on the sensor. Available communication
methods are shown in the table below (see Section 2.3 Cabling for
information on maximum cable lengths).
Connection Description
4-20 mA Analogue output
RS485 Digital output, suitable for long-distance cabling.
5.5.1 4-20mA Communications
Refer to Section 5.2.5 for instructions on setting the 4-20mA output.
5.5.2 RS-485 Comms Settings [R485]
Set the RS-485 communications settings using the address switch on the
instrument (see Section 4.5.5 for details).
5.6 Sensor Checks and Controls
5.6.1 Sensor Checks
Sensor checks are provided as standard on the 4750-PM , both for auditing
purposes and to provide quality assurance. The following sensor tests are
available:
•
Manual Zero and Span checks, which are run from the sensor on
demand;
• Purge Air Flow check (optional automatic sensor self-check; requires a
Purge Air Flow sensor; see Section 2.2.3). This is a standard feature on
high-temperature sensors. The air purge flow check monitors the purge
air flow continuously. Test failure suggests that purge air is not present
or insufficient.
Sensor Check
Minimum
Pass Level
Ideal Level
Maximum
Pass Level
Zero test -2 0 2
Span test 90 100 110
Purge Air Flow Self-check 5
G
20-40 -
G
If the purge air flow falls below the minimum threshold, the purge
blower filter should be changed.
NOTES
(i) If the tests have not been run yet, then [- -] is displayed
for the ZERO and SPAN settings (and FLOW, if available). If
required, initiate the sensor tests manually (see Section 5.2.9
for instructions).
(ii) If available, the Purge Air Flow check runs continuously.
(iii) No values are shown while the tests are running. Wait for the
Self-check LED to stop flashing (see next section).