Masoneilan SVI II AP Digital Positioner Quick Start Guide
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Compliance Voltage in Single Drop Current Mode
The SVI II AP requires 9.0 V at 20 mA and 11.0 V at 4 mA. Typical HART
®
devices require MORE
Voltage at higher current and MORE current source have LESS Voltage available at higher cur-
rent. The SVI II AP is noteworthy in that it requires LESS Voltage at higher current that comple-
ments the characteristic of the source requiring only
9 V at 20 mA
.
Verify Wiring and Connections
NOTE
For split range installations the compliance voltage must be
capable of the minimum span being 5 mA; the upper range value
must be 8 mA
to 20 mA; the lower range values must be 4 mA to
14 mA.
Use the following procedure to ensure that the SVI II AP is properly powered:
1. Connect a DC voltmeter across the input terminals.
For an input current between 4 and 20 mA the voltage varies between
11 V and 9 V respective.
When voltage exceeds 11 V check that polarity is correct.
If voltage is less than 9 V and polarity is correct, voltage compliance of
current source is inadequate.
2. Connect a milliampmeter in series with the current signal.
3. Verify that source can supply 20 mA to SVI II AP input. If 20 mA is not attainable,
troubleshoot the source and set up.
NOTE
Improperly or inadequately grounded installations can cause
noise or instability in the control loop. The internal electronic
components are isolated from ground. Grounding the case is
unnecessary for functional purposes but grounding the case may
be necessary to conform to local codes.
