Yokogawa digitalYEWFLO (DY) - Manual (Page 77)

MAINTENANCE
IM 1F2B4-01-YIA
Page 81
4.5 YEWFLO S
TYLE
"E" A
MPLIFIER
C
ALIBRATION
P
ROCEDURE
Before calibrating the YEWFLO style E you will need to have the following tools on hand:
Item Recommended Instruments Remarks
Power Supply 24 VDC ±10% (Ripple < ±50mV)
Load Resistance (250 ohm) ±0.005% 4-20 mA DC version only
Voltmeter Model 2506A digital multimeter (accuracy ±0.05%) 4-20 mA DC version only
Oscilloscope Optional Optional
BRA IN terminal BT100 or BT200 handheld terminal For parameter setting
The YEWFLO Style “E” amplifier is microprocessor-based and in normal operation the span vs.
output relationship is checked automatically through the microprocessor’s calculations. If it is
necessary to prove the span/output relationship or generally check the correct operation of the
amplifier, the following procedure can be followed. The procedure consists of two sections.
Section 4.5.1 may be performed independently, but Section 4.5.2 and/or 4.5.3 should be
performed only after Section 4.5.1 has been completed.
Figure 4.5.1
If the amplifier is checked in the instrument shop, be sure the amplifier case is well grounded. On
remote amplifiers, besides grounding the case be sure to short terminals A, B, and C and ground
them to the case. If checking an amplifier on a meter in-line, be sure the amplifier is well grounded
and a no-flow condition exists.
Connect the amplifier as shown in 4.5.1. Apply power for at least five minutes before testing.
Before beginning, check to be sure that all parameter settings are as specified in the programming
sheet which was included with the flowmeter instructions. If there is any discrepancy, correct the