Bird Technologies 4421 - Manual (Page 43)

RS-232 Interface
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Remarks Prefixes are sent over the bus with the measurement, and indicate the status
of the current measurement (see Table 6-18 for examples):
z “FC”,”FD”,”RC”,”RD”,”SW”,”RL”,”MN”,”MX” indicates the measure-
ment type.
z “U” indicates underflow; the value sent is “.000”.
z “O” indicates overflow; the value sent is “199.9”.
z “N” indicates normal; the value sent is a normal on-scale reading.
z “4421” indicates the Bird model number.
Table 6-18 Prefix Examples
Triggers (Tx)
Function Selects the condition which will trigger a reading (see Table 6-19).
Remarks Failure to trigger device before requesting a reading will lock the bus.
Fastest reading rate is 2.4 readings/second; slowest is 1 reading/sec.
Table 6-19 Trigger Conditions
Status (Ux)
Function Reads a status word and returns the information as a string. Set x to:
z “0” for machine status.
z “1” for error status.
z “2” for revision history.
Remarks After sending the status command, a status word is sent the next time the
unit is addressed to talk. To ensure the correct status is transmitted, the sta-
tus word should be requested as soon as possible after the command is sent.
Data String Description
NFC.0.123W(CR)(LF)
Normal (N) forward carrier wave (FC), prefixes on
OFC 199.9W(CR)(LF)
Overflowed (O) forward carrier wave (FC), prefixes on
199.9W(CR)(LF)
Overflowed forward carrier wave, prefixes off
URD .000W(CR)(LF)
Underflowed (U) reflected dBm (RD), prefixes on
Command Trigger Condition
T0 Continuous on ENT
T1 One shot on ENT
T3 One shot on TRG
T5 One shot on measurement command (FC, FD,
RC, RD, SW, RL, MN, MX)