Hach BioTector B7000 User Manual page 110

SIGNAL UPDATE
UPDATE LEVEL
UPDATE PULSE
OUTPUT < 4mA
NO  SIGNAL UPDATE, which is deactivated with the "NO" setting by
default, defines whether the programmed 4-20mA signal
channels are going to signal the update of the 4-20mA signals or
not before a new 4-20mA signal is sent.
 This function only operates in DIRECT output mode and it helps
the user to identify the new 4-20mA result without additional
output signals and system wiring.
 When SIGNAL UPDATE is programmed as YES and activated,
3.0 mA
the 4-20mA signal at the programmed channels, are dropped to
the programmed UPDATE LEVEL, which is 3 mA by default,
before the new 4-20mA result signals are sent to the relevant
channels.
 As it is not meaningful to program both FAULT LEVEL and
UPDATE LEVEL at the same 4-20mA level, when this happens,
BioTector assumes that the FAULT LEVEL setting is the master
and automatically changes the UPDATE LEVEL back to its
default 3.0mA setting or sets it automatically to 0.0mA.
5 s  When SIGNAL UPDATE is programmed as YES and activated,
the 4-20mA signal at the programmed channels are dropped to
the programmed UPDATE LEVEL for the duration of the
UPDATE PULSE time, which is 5 seconds by default, before the
new 4-20mA result signals are sent to the relevant channels.
 OUTPUT < 4mA function defines the factor (0% by default) to be
0%
applied on the stream value if the output value becomes smaller
than 4mA (negative result). This function allows the user to
clamp or reduce the effect of negative result on the 4-20mA
output value.
 For instance, if the OUTPUT value is set as 100%, 100% of the
negative result is sent as 4-20mA signal. If the setting is 50%,
50% of the negative results is sent as 4-20mA signal. When the
setting is 0%, no negative result is send and any negative result
is clamped to 4mA (0mgC/l) level.
Page 110