Sponsler Co., Inc.
SP718-mA Modulated Carrier Amplifier
pg 3
DOC# MN-718MA-A
Digital Multimeter (DMM)
Frequency Generator
Frequency Counter
Oscilloscope
Refer to Figure
Test Procedure:
NOTE:
All test equipment power cords should be equipped with 2-prong ‘cheater’ plugs.
A)
Connect Flowmeter with RF Pick-up Coil to J1-1,2
B)
Connect Power Supply Positive (HOT) & Negative (NEU) Leads to J1-6,5
Respectively
C)
Connect O’Scope Positive & Negative Leads to J1-1,2 Respectively
D)
Connect DMM Positive & Negative Leads to J1-3,4 Respectively, Set Function to mA
DC
E)
Install Jumper @ JU1-3 for desired Full Scale Frequency Range
F)
Turn Power Supply ‘ON’, LED D1 Illuminates & O’Scope displays a 50KHz +/- 5KHz
6Vp-p Carrier Sinewave
G)
Adjust ‘ZERO’ (R25) for a DMM Indication of 4.00mA
H)
Set Frequency Generator function to Sinewave, Amplitude to 500mVp-p with 2.5VDC
OFFSET & Frequency to desired Full Scale Frequency. Connect Frequency
Generator POSITIVE Lead to TP1 (R11) & NEGATIVE Lead to J1-2.
I)
Adjust ‘SPAN’ (R23) for DMM Indication of 20.00mA
J)
Reduce Signal Amplitude of Frequency Generator to Zero, Adjust ‘ZERO’ (R25) for
DMM Indication of 4.00mA if necessary
K)
Increase Signal Amplitude of Frequency Generator to 500mVp-p, 2.5VDC OFFSET;
Adjust ‘SPAN’ (R23) for DMM Indication of 20.00mA if necessary
L)
Adjust Frequency of Frequency Generator to 0, 25, 50, 75, & 100% of Full Scale
Frequency of Step H
To check for Linearity at any Frequency Point, incorporate the following formula -
(F/F Max X 16) + 4 = mA
Example: Assume Maximum Frequency Point = 2KHz (20mA Point)
Check for Linearity at 750Hz
750/2000 = .375
16 X .375 = 6
6 + 4 = 10 DMM Should indicate 10.00mA at 750Hz
