Max Machinery 276-5XX SERIES 4-20MA TRANSMITTERS - Manual (Page 8)

( 8 ) 276-515-350 © 2006 Max Machinery, Inc.
USER OPTIONS & ADJUSTMENTS
—Damping & Output Over Range LED
Damping: R37/38/39 or R49/50/51. The 276 Transmitter has a damping network which is used
to average out meaningless variations in the output current which can result from system layout,
pump noise, or Flowmeter design. To adjust the damping, set the flow rate to the lowest flow
that will typically be used. Increase the setting of the three damping potentiometers equally until
the indicated flow rate shows the desired stability. Increasing the damping will also slow the
response to actual flow rate changes, so use the minimum damping necessary.
Output Over Range LED: This LED will start to blink if the Transmitter output amplifier begins
to saturate (clip). This happens when the flow rate or gain is too high. Clipping will cause the
output current to be less than it should be and not a true indication of flow rate. The figure below
shows what happens as the flow rate is increased to the point at which the output is saturated.
The flow rate in a system may have as much as 50% to 100% ripple. This may be caused by the
pump, by air in the line, or a slightly sticky Flowmeter. The maximum output current of the 276
Transmitter must be kept low enough so that the output is not saturated. This may mean that the
average full scale output current will have to be less than 20mA to avoid clipping the peaks in
the output signal, as indicated in the figure below.
Discontinued