Yokogawa ADMAG AXR - Manual (Page 65)

<6. PARAMETER DESCRIPTION>
6-17
IM 01E30D01-01EN
NOTE
If the flow rate units, time units, and flow
rate span are specified upon ordering, these
parameters will be setup before shipment;
however, if this is not the case, it will be
necessary for the appropriate values to be set up
by the user.
NOTE
Flow rate span is the value for instantaneous
flow rate that corresponds to a current output of
20 mA. The following factors should be taken
into consideration when deciding on the flow rate
span.
• In the case of applications with large
variations in flow rate, the maximum flow rate
should be set. If a flow rate in excess of the
flow rate span was to occur, output would be
possible up to an upper limit of 103.13%, and
beyond this, error would occur. Note that the
same applies to pulse output and totalization.
• In the case of applications that have a
relatively stable flow rate, a flow rate span of
1.5 to 2.0 times larger than the normal flow
rate may be considered suitable.
• The flow rate to be adopted should - upon
conversion to flow velocity - correspond to
a value within the range of 0.3 to 10 m/s.
The flow velocity can be confirmed using
sizing data or with parameter C44: Velocity
Check, and in the latter case, the value
obtained when span is converted to flow
velocity will be displayed.
• Regardless of the position of the decimal
point, the largest value that can be set on the
display unit is 32,000. Furthermore, it is not
possible to set a number of 4 or greater for
the highest-order digit. Similarly, if 3 is set for
this highest-order digit, it will not be possible
to set a number of 2 or greater for the next
digit to the right, regardless of the position of
the decimal point.
Example: A value of 333.33 is represented
by the character string 33333, and
since this exceeds 32000, it cannot
be set. In such a case, the value
333.3 should be set instead.
[B24: Flow Decimal Pnt] Setting of the decimal
point position for the instantaneous flow rate
→ This setting is linked with that of parameter C43.
This parameter sets the position of the decimal
point for instantaneous flow rate values in terms
of the number of digits. When set using “Auto”,
the decimal point position will be automatically
determined in accordance with the setting value for
B23/C42: Flow Span as shown below.
Flow Span ≤ 9 Decimal point position:
3 digits
9 < Flow Span ≤ 90 Decimal point position:
2 digits
90 < Flow Span ≤ 900 Decimal point position:
1 digit
900 < Flow Span Decimal point position:
no digits (i.e., no decimal
point)
When an item other than “Auto” is set, the selected
number of digits for the decimal point position is
used.
With the decimal point removed, 6 digits are
available for the instantaneous flow rate value, and
display is possible up to 999,999. If an overflow
occurs as a result of the setting adopted for decimal
point position, the warning 84: Disp Over Wng will
be displayed to provide notification of this condition.
Example: When 1000 m 3 /h is set for B23/
C42: Flow Span
Item Display content for instantaneous flow rate value
Auto 1000 m 3 /h
0 1000 m 3 /h
1 1000.0 m 3 /h
2 1000.00 m 3 /h
3 With the decimal point removed, 7 digits are not
available for the instantaneous flow rate value;
therefore, a warning is displayed.