RFL 9780 RFL Electronics Inc.
April 8, 2003 4-12 (973) 334-3100
4.8 INITIAL STARTUP PROCEDURE
After the 9780 is installed and prior to being placed in service, a few basic adjustments and
measurements must be performed to ensure proper operation. The output power of the system should
be verified and adjusted if required, the output impedance of the transmitter must be adjusted to match
the actual impedance of the line, and the receiver must be adjusted for the actual receive signal level.
This section assumes that the equipment has been installed and configured for the required application
in accordance with Section 3 and paragraph 4.3. Note that the modules in the 9780 are not hot
pluggable. The power to the chassis must be turned off prior to plugging or unplugging any modules.
4.8.1 EQUIPMENT REQUIREMENTS
The following equipment is required to perform the initial startup procedures:
1. Frequency-selective voltmeter (FSVM)
2. Potentiometer adjustment tool (or small flat-blade screwdriver)
3. 50 ohm (non-inductive) dummy load
4. PLC Test Set (Signal Crafters Model 70 or equivalent)
5. Optional module extender card (RFL part number 9547-1870)
4.8.2 TRANSMITTER
It is advisable to verify the operation of the transmitter after installation into the system. This allows
checking the 9780 and line tuning equipment.
4.8.2.1 Output Power
The 9780 transmitter is specified to provide 10 W into a 50 ohm load. Adjustments to the output power
are made with a 50 ohm dummy load connected. Any additional devices in the transmit path, such as
hybrids, will reduce the effective output power. This adjustment should be performed at the rated 10 W
level.
1. Connect the dummy load to the system output (the “Tx” port if there is no hybrid in the system or
the “Line” port if a hybrid is installed.
2. Connect the FSVM across the output of the Output Filter Module at TP2 (blue) and TP1 (brown).
Set the FSVM to the transmitter output frequency.
3. Set the transmitter to output the full 10 W level (such as keying the trip input on a typical 1W/10W
system). Verify that the “PWR 3” LED on the Transmitter Module is lit. Note that it is preferable
to set the transmit level at 10 W, however, the adjustment can be made at 1 W or 3 W.
4. Adjust the Power Amplifier Gain control (R2 on the rear of the chassis) to achieve 22.36 Vrms (40
dBm). If it is impractical to set the transmitter for 10 W, the level can be adjusted to 12.25 Vrms
(34.8 dBm) for 3 W or 7.07 Vrms (30 dBm) for 1W.
5. Disconnect the dummy load and restore the line connection.
To Next Page
Loading...