ABB ETL600 Instruction Manual page 296

Revision:
A
B.6.4 Tune RF hybrid P3LE
Tuning is only necessary for high performance measurements, for a custom approval of the
equipment or for long power lines with high signal attenuation.
Note:
If the hybrid is not tuned, default settings must be used:
- Set the line balancing network jumpers RA, LP, CD and CE und put the remaining C-jumpers in
P position.
- Set the hybrid impedance to the impedance of the attenuator, i.e. 45, 75 or 125 Ohm with
jumpers LNx, Mx and Nx, where x=1 for 45 Ohm, x=2 for 75 Ohm and x= 3 for 125 Ohm.
The RF line coaxial cable is connected to the equipment. The PCB extender type I9BK or the Tx
tuning adapter P3LL is inserted in place of the RF hybrid P3LE and the RF hybrid is plugged on top
of it.
The settings on P3LL if used are:
•
Function:
•
Position of S1:
•
Position of S2:
•
Position of S3:
•
Position of LOAD:
Tuning the hybrid using the HMI600.
1. On the Equipment menu click Tuning & testing. This opens the Tuning & testing dialog
box.
2. Click Tune RF hybrid. This opens the Tune RF hybrid dialog box.
3. Check the jumper settings on the hybrid: RA, LP, CD and CE. The remaining C-jumpers
in P position.
Depending on the impedance of the attenuator, set the hybrid impedance to 45, 75 or 125
Ohm with jumpers LNx, Mx and Nx, where x=1 for 45 Ohm, x=2 for 75 Ohm and x= 3 for
125 Ohm.
4. Click Start measurement and wait until the measured Rx RF level appears in the dialog
box.
Note:
5. The HMI600 selectively measures the level of the RF signal from the own transmitter.
This level is set to a minimum with the aid of a balancing network (resistance with jumper
RA/RB/RC/RD/RP and potentiometer R226, inductance with jumper LA – LN/LP and
capacitance with jumpers CA to CL, CP) as described below.
6. Reduce the measured Rx RF level moving the R-jumper between RA, RB, RD, RD and
RP. When the best jumper position has been found, turn potentiometer R226 until a first
minimum is reached.
7. Search for the next minimum by moving the L-jumper sequentially to LA, LB, LC, ..., LN.
If, however, jumper LA does not produce any reduction, set Jumper LP. (LA produces the
smallest inductive current and LN the largest).
Note:
8. If a minimum could be achieved with LA to LN, reduce the measured Rx RF level
again to the next minimum using potentiometer R226. Further improvement can be
achieved using small capacitor values with jumpers CA, CB or CC. C jumpers may be
inserted in parallel.
This concludes the tuning of the hybrid.
Click Stop measurement and Cancel to close the dialog box.
Language:
EN
The tuning is not necessary when the ETL600 is operated without Rx filter
P4RX.
B
L1, FILTER
FILTER
LINE
LINE
It is possible that the operator phone of remote equipment is ringing during
the measurement. This has no effect on the measurement.
Only one L jumper (LA – LN) may be inserted at any one time
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