RS-232 Interface
31
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
T
riggers
(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)
