AR 10006031, Operating And Service Manual

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Model 200T4G8
3.7 Emergency Bypass Operation
For reference, see schematic 10-24369-000 in section 5.2.
The TWTA is provided with a means of operating the amplifier manually in the event that there is a failure of
the control module and it is imperative that the amplifier remains on line.
CAUTION:
Emergency bypass operation disables external interlock and certain
protective and diagnostic features. For this reason, the emergency bypass
mode of operation should be used only when the control unit fails and
when it is essential to remain on line.
To access the manual controls, remove the two 4-40 screws securing the Emergency switch cover plate on the
front panel. Emergency bypass mode is selected by pushing the left-hand switch (S1) to the left. The center
switch (S2) toggles between high voltage on (left) and high voltage off (right). The right-hand switch (S3)
selects between beam on (left) and beam off (right). There is a manual control for the gain adjustment as well.
This is a flat, square single-turn pot (R1).
CAUTION:
Do not adjust 20-turn pot R11; its function is to set the foldback VSWR
level, and it is calibrated at the factory.
3.8 REMOTE IEEE-488 OPERATION
The TWTA is provided with an IEEE-488 interface that permits remote emulation of OPERATE,
STANDBY, and RESET push-buttons as well as access to parameter measurements, system faults, and
control unit status. The following tables summarize the commands and the return codes.
Table 3-3. Catalog of IEEE-488 Commands
Command Function Units Response format
RDSTAT
Returns status code of processing of previous command (see Table
3-4)
STATUS=[ ]
RDFLT Returns system fault code (see Table 3-5) flt=[ ]
OPERATE; Emulates OPERATE push-button
STANDBY; Emulate STANDBY push-button
POWER:OFF; Emulate STANDBY push-button
RESET; Emulates RESET softkey
RDS/N Returns serial number s/n=[ ]
RDCONHR Returns console hours ConHr=[ ]
RDRFHR Returns RF hours RfHr=[ ]
RDEK Returns cathode voltage KV Ek=[ ]
RDEB Returns collector voltage KV Eb=[ ]
RDEG (or RDEA) Returns grid (or anode) voltage V Eg=[ ] (Ea=[])
RDEF Returns heater voltage V Ef=[ ]
RDIF Returns heater current A If=[ ]
RDIW Returns helix current mA Iw=[ ]
18 Rev. F