Yamatake Corporation
Maintenance and Troubleshooting
ST3000 Smart Transmitter Series 900 Electronic Differential Pressure/Pressure Transmitter
7-35
7-7 : Insulation Resistance Test and Withstand Voltage Test
CAUTION
In principle, do not perform an insulation resistance test or a withstand voltage test.
In some cases, the built-in varistor with a function for absorbing surge voltage surges
may be destroyed during these tests.
If a test must be performed for an unavoidable reason, carefully follow the following
procedures.
Test procedure
• Disconnect the external cables from the transmitter.
• Short-circuit the + and - SUPPLY terminals and the + and - METER terminals.
• Perform a test between the short-circuited parts and the ground terminal.
• The required impressed voltage and the judgement criteria are shown below. Don’t
apply higher voltage to protect the instruments from destruction.
Judgement criteria
Test
Judgement criteria
Insulation resistance test
Ω
or higher at test voltage of 25V
DC (Not higher than 25°C and 60%RH)
Withstand voltage test
50V AC, 1 minute, set current 2mA
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