Solid State Scott-T converter
Syncro signals must be converter to SIN and COS resolver signals that can be directly
be interfaced by the Resolver-to-Digital converters. The classical transformer coupled
connection is often too cumbersome to use. The ERES104 module uses the internal
operational amplifiers of the Resolver-to-Digital converters and prescision resistors to
implement the Solid State Scott-T circuit seen below. The most important design criteria in
this connection is the perfect matching of the resistors. Precision is maintained by using a
special trimmed resistor network together with the internal Opamps. These resistor networks
are available for the two standard voltage levels 11.8V and 90V syncros. The resistor network
value ratios are pre-trimmed to produce the 2V rms input signal required by the converters.
Jumper fields A, B and C as discussed previously will select the right resistor configuration
for the circuit.
You may separately purchase resistor networks for both standard voltages from RTD.
They may be easily configuraed channel-by-channel by inserting the correct resistor network
into the onboard sockets. The resistor networks are used as follows:
DDC - 49530 are used with 11.8V Syncro inputs
DDC - 49590 are used with 90V Syncro inputs
Fig. 3-4 Solid State Scott-T converter circuitries.
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ERES104 Ver 1.2 (c) RTD Finland Oy 2000-2001