BIRD SMK-3000 Series, User Manual

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RF Calibration Kit
24
Device Dependent Commands
The device-dependent commands used by the 4421 Power Meter are listed in Table 6 , organized by category.
Table 6 RS-232 Device Dependent Command Summary
F
orward
C
arrier Wave (FC)
R eflected C arrier Wave (RC)
R ange (RYY)
Terminators (YT)
P refixes (PY)
Category Command Description
Measurement
FC Forward carrier wave
RC Reflected carrier wave
Range RYY
Auto range on
1
1 dummy command, the setting they control has only one option.
Terminators YT
Two terminators: CR, LF 1
Prefixes PY
Prefix YES 1
Triggers
T1 One shot on ENT
T5 One shot on measurement command
Function
Selects forward or reflected RF power measurement mode.
Remarks
Measurement results are returned in Watts.
Function
Sets the 4421A to auto range, legacy command to provide
compatibility with previous 4421 units.
Remarks
Auto is the only range setting available.
Function
Selects the characters that follow the end of a data string. YT
indicates for two terminators; a carriage return (CR) and a line
feed (LF).
Remarks
Many controllers use the terminator sequence to recognize the
end of an input string. Using incorrect terminators can lock the
bus.
Function
Turns the prefix mode on.
Remarks
Prefixes are sent over the bus with the measurement, and
indicate the status of the current measurement (see Table 7
for examples):

“FC”,”RC” indicates the measurement type.

“U” indicates underflow; the value sent is “.000”.

“O” indicates overflow; the value sent is “199.9”.

“N” indicates normal; the value sent is a normal on-
scale reading.

“4421” indicates the Bird model number.