Cameron NUFLO MC-III, Руководство пользователя

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MC-III™ Panel Mount Flow Analyzer Section 4
4-20 mA Output
Caution: Before performing any 4-20 mA calibration, ensure that all peripheral equipment connect-
ed to the 4-20 mA current loop is either disconnected or disabled. Calibrating and test-
ing the 4-20 mA output feature on the MC-III Panel Mount with the peripheral equipment
in operation may cause false alarms or erroneous operation of the peripheral device or
associated equipment.
The 4-20 mA Output screen (Figure 4.27) allows users to configure the MC-III Panel Mount to provide a
4-20 mA output representing flow rate. Zero and full-scale values can be configured to represent any flow rate
range within the range of the flow meter. A test mode function is also included, allowing a user to calibrate
and/or verify the output received by an end device.
Figure 4.27—4-20 mA Output screen
The low (or zero) setting is the flow rate value that will produce a 4-mA output. The high (or full-scale)
setting is the flow rate value that will produce a 20-mA output. Typically, the high value is greater than the
low value; this scenario is defined as “direct mode” in
Figure 4.28, page 64
.
Alternatively, users may configure the 4-mA and 20-mA outputs to have an inverse relationship, such that the
high value is less than the low value. This scenario is defined as “indirect mode” in Figure 4.28, page 64 .