Rate Alarm Outputs
The flow rate output permits output changeover at two separate flow rates, allowing operation with an adjustable switch
deadband. Figure 29 illustrates how the setting of the two setpoints influences rate alarm operation.
A single-point flow rate alarm would place the ON setting slightly higher than the OFF setting, allowing a switch deadband to
be established. If a deadband is not established, switch chatter (rapid switching) may result if the flow rate is very close to the
switch point.
Minimum
Flow
Maximum
Flow
Output ON
Set OFF
Set ON
Deadband
Output OFF
Figure 28: Single point alarm operation
OTE:N All control outputs are disabled when a USB cable is connected.
Signal Strength Alarm
The SIG STR alarm will provide an indication that the signal level reported by the transducers has fallen to a point where flow
measurements may not be possible. It can also be used to indicate that the pipe has emptied. Like the rate alarm described
previously, the signal strength alarm requires that two points be entered, establishing an alarm deadband. A valid switch
point exists when the ON value is lower than the OFF value. If a deadband is not established and the signal strength decreases
to approximately the value of the switch point, the output may chatter.
Batch/Totalizer Output (Flow-Only Model)
Totalizer mode configures the output to send a 100 mSec pulse each time the display totalizer increments divided by the
TOT MULT. The TOT MULT value must be a whole, positive numerical value. This output is limited to 1 Hz maximum.
For example, if the totalizer exponent TOTL E is set to E0 ×1 and the totalizer multiplier TOT MULT is set to 1, then the
output will pulse each time the totalizer increments one count, or each single, whole measurement unit totalized.
If the totalizer exponent TOTL E is set to E2 ×100 and the totalizer multiplier TOT MULT is set to 1, then the control output
will pulse each time the display totalizer increments or once per 100 measurement units totalized.
If the totalizer exponent TOTL E is set to E0 ×1 and the totalizer multiplier TOT MULT is set to 2, the control output will
pulse once for every two counts that the totalizer increments.
Error Alarm Outputs
When a control output is set to ERROR mode, the output will activate when any error occurs in the transmitter that has caused
the transmitter to stop measuring reliably. See “Brad Harrison® Connector Option” on page95.
Inputs/Outputs
Page 27 May 2016 TTM-UM-00136-EN-06
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