Revision 1 87 9/10/2019
purge with the new gas for as many seconds as the number in this field, then advance the
tape again before starting to analyze the new stream. The longer this number is, the better
the results will be on the next stream. A minimum time in this field should be about 30
seconds.
5.9.1.1 Tape Field
The Imperial (Feet) and Metric (Meter) radio buttons are used to indicate the units used for
the tape box. Selecting between the two does not recalculate any numbers in the Tape box –
these two buttons are simply used to allow the user to see at a glance what units the
numbers in the Tape box are in. By default, the analyzer is set up to use imperial units for
tape.
• Stain Width - shows the width, in feet or meters of a single stain on the tape. This field is
calculated based on values in the next two fields.
• Stain Width per Pulse - shows the distance that the tape advances every time the pulse
counter receives a pulse.
The calculation of Stain Width per Pulse is typically performed only if the pulley on the pulse
counter needs to be replaced.
To calculate the value:
a) Measure the diameter, in inches, of the pulse counter pulley using a set of calipers.
b) Multiply this number by π to get the circumference of the pulley; then divide the result by
12 to get the circumference of the pulley in feet.
c) The Pulse Counter receives 256 pulses every time it makes one full revolution, so
dividing the circumference of the pulley in feet by the number of pulses per revolution will
give the length of tape advanced when the pulse counter receives one pulse. This is
expressed in the following formula:
Stain Width per Pulse (feet) = ((Diameter
(inches)
x π) / 12)/256
The formula can also be expressed in metric format as follows:
Stain Width per Pulse (meters) = ((Diameter
(millimeters)
x π)/1000)/256
If a metric value is entered into this field, the value in the Stain Width field will also be in
metric format. When the Accept button is pressed, the value in the Stain Width field will be
recalculated.
The Stain Width In Pulses field allows the operator to choose how many pulses the pulse
counter should receive before stopping a tape advance. The larger the number in this field,
the greater the stain spacing will be. The smaller the number in this field, the more overlap
there will be between stains. By default, this number is set to around 40. If the spacing is too
great with a value of 40, reduce this number to around 37 and check stain spacing again. Too
much overlap between subsequent stains will cause poor results. Too much white space
between subsequent stains will cause faster than desired tape usage. The maximum value
that can be entered into this field is 99. If the user enters a value higher than this into the field
and attempts to write it to the analyzer, the field will turn yellow, indicating that an invalid
value has been entered. Enter a value between 1 and 99 into this field and then press the
Accept button.
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