Transmitters and Carriers
Gas turbine applications frequently require large numbers of strain and temperature measurements - and this means installation of a number of transmitters plus inductive power hardware, into whatever space is available.
(Click on thumbnails to enlarge)
18 rectangular design single channel strain transmitters, 27kHz bandwidth. Housed in 175mm diameter titanium carrier. Operated at 27,000 RPM and 145°C.
32 rectangular design multi-channel strain and thermocouple transmitters in 190mm diameter titanium ring form carrier. Operated at 27,000 RPM and 145°C. A central hub is temporarily fitted for spin testing purposes.
Set of 40 transmitters on a spin test carrier - 60 strain gauge and 160 thermocouple channels.
Part of 840 channel system for power generation Gas Turbine validation.
One of four 0.86M diameter transmitter carrier rings used on a massive 860
channel systems supplied to General Electric for validation of the 9H power
generation gas turbine.
A 2 channel strain transmitter as used in the General Electric 9H system.
Inductive power pickup and signal transmission antenna are incorporated into
Demodulators and Decoders
All demodulator systems are based upon the universal 19" rack x 3 units high caseframe, with plug-in modules incorporated according to system size and complexity. The smallest systems used for gas turbine applications tend to be in the range 10-15 channels and for these, simple stand-alone demodulator modules are available.
For larger systems of up to 1024 channels, single, 2 and 5 channel demodulators may be set-up and operated via remote control, using the inductive power supply transmit setup data commands to the transmitters. A laptop or P.C will generally be used as an input and local display.
Summary of available commands to transmitters:
- ■ Activate shunt calibration - typically 1kHz or 10kHz
- ■ Set excitation current (single gauge strain transmitters)
- ■ Turn off excitation current
- ■ Set excitation voltage(strain gauge bridge transmitters)
- ■ Null inputs to zero (strain gauge bridge transmitters)
- ■ Adjust input sensitivity
- ■ Turn on simulated triangle or square waveform (check A/D linearity)
- ■ Fine tune transmitter carrier frequency
Summary of available commands to demodulators:
- ■ Set tuned frequency
- ■ Set capture range of A.G.C
- ■ Set to auto-tune or manual fine tune
- ■ Adjust zero
- ■ Fine adjustment of output scaling
Typical Astech "Monitel" control software display showing setup and status for 27 x 2 channel strain transmitters and 1 x 15 channel thermocouple transmitter.