APT3500 Smart Pressure Transmitter
Operation Manual M3500-EO1G
61 DUON System Co., Ltd.
6.4 Hardware Maintenance
Autrol APT3500 Smart Transmitters have no moving parts and require a minimum of scheduled
maintenance. Both transmitters feature modular design for easy maintenance. If you suspect a
malfunction, check for an external cause before performing the diagnostics as discussed later in this
section. If you must return failed transmitters or parts, send them to DUON System Co., Ltd. for
inspection, repair, or replacement.
6.4.1 Test Terminals
The test terminal, marked as TEST on the terminal block. The test and negative terminals are
connected to the test terminals; so long as the voltage across the receptacles is kept below the
diode threshold voltage, no current passes through the diode. To ensure that there is no leakage
current through the diode while making a test reading, or while an indicating meter is connected,
the resistance of the test connection or meter should not exceed 10 ohms. A resistance value of
30 ohms will cause an error of approximately 10 percent of reading.
[Figure 6.1 Test Terminals]
Local Indicator
or Current Meter
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+