Operation Manual

8-3
IM 1F5B2-01E
8. MAINTENANCE
8.2 Adjustment
This section explains the procedure used to adjust the ULTRA YEWFLO converter to
change the range or for other purposes. Adjust the converter in a maintenance room
complete with the equipment necessary for adjustment.
8.2.1 Zero Adjustment
■ No zero adjustment is necessary since the zero point does not shift.
IMPORTANT
• Because of the effect of electrical noise, ULTRA YEWFLO may provide an output
even when the flowrate is zero. In that case, properly eliminate the source of the
noise.
8.2.2 Span Adjustment
•Before span adjustment, check whether the range of the flowrate is adjustable or not
by following the instructions in Section 6.1, “Checking the Flowrate Range.” Spans
are automatically determined and set when you configure required parameters with a
BT200 BRAIN Terminal. Therefore, in normal applications, you need not confirm
the spans once they are set up. If you are verifying the analog output, follow the
procedure on the Verification Procedure.
Verification Procedure
<1> Wire the necessary pieces of equipment as shown in Figure 8.1-1. Allow at least
three minutes for the equipment to warm up.
<2> Configure the necessary parameters.
<3> Set span frequency with parameter F20: SET F MODE. (See the equation noted
below.)
<4> If the load resistance is 250 Ω, the digital multimeter should read 5 V. Make sure
the multimeter indicates the value calculated from R × 20 (mA) when a resistor of
a known value (R Ω) is used.
<5> Next, set parameter F20 at a frequency equal to 50% of the full-scale frequency.
Make sure the analog output is within the specified limits of accuracy.
<6> Finally, set parameter F20 at 0 to make sure the analog output is still within the
specified limits of accuracy.
• Equation for Determining the Span Frequency
f = KM • [1 - 5.25 × 10
-5
× (t - 15)] • Qf
where
f = span frequency (Hz)
Qf = maximum (span) flowrate (l/s)
KM = K-factor (p/l) (indicated on the data plate)
t = temperature of the fluid under operating conditions (°C)
• Simply configure the necessary parameters. The built-in microprocessor automati-
cally calculates the frequency at the maximum flowrate (span frequency). The span
frequency is indicated under parameter G11: SPAN F.