Vishay Precision Group LVD 3, Инструкции по эксплуатации и монтажу

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LVDT Signal Conditioner LVD 3
13
Signal conditioner module
Figures 2 and 5.
First check the connections and that all relevant switch settings on the board have been done.
Select primary feedback, (SW2 in position ‘PRIM.’) to simplify the fault finding.
Then check the module in conjunction with the transducer.
Power supply
Check the power supply to the module, measuring with a DC voltmeter:
+24 V DC at terminal 11, 0 V
24
at terminal 12.
Observe that the module has one internal fuse for each channel.
Output from oscillator
Check the output signal from the oscillator to the transducer primary coil, measuring with an
AC voltmeter:

3.3 – 3.5 V AC at terminals 1 and 2.
If there is no voltage, disconnect the transducer and check the output again.
If there is still no voltage, (NOTE, SW2 must be set for primary feedback), it
indicates that the internal fuse may be blown. In other cases there is a fault
in the oscillator, and the circuit board must be changed.
If the fault disappeared, the transducer and transducer cable must be checked
with respect of short ‐ circuits.
If the oscillator function is correct you can proceed
and check the input signals
from the transducer.
Input signals from transducer
Input signals to LVD 3 from the transducer can be checked at the test sockets
Sec. 1 and Sec. 2. First ensure that the transducer primary coil is supplied from
the oscillator, measuring at test sockets Prim. – Com. (3.3 – 3.5 V AC).
Then check the AC voltage at Sec. 1 – Com. and Sec. 2 – Com. respectively.
Check that the voltage decreases for one coil and increases for the other when
the transducer core position is changed.
Also check that the AC voltage between Sec. 1 and Sec. 2 is close to zero
when the transducer core is in the centre position. If not, the connections for
one of the secondary coils must be reversed.
If this checking with primary feedback is satisfactory, faults in the oscillator, transducer and
transducer cable can be excluded.