Bench test calibration procedure – Liquid Controls SP712-2 REV. B User Manual
Page 3
Sponsler, Inc.
SP712-2 Transmitter
pg 3
DOC#: MN-712-B
Z
E
R
O
S
P
A
N
S1
R1
SP712-2
1
0
0 = 100-1000Hz
1 = 1 KHz-10KHz
SENSITIVITY
BENCH TEST CALIBRATION PROCEDURE
Required Equipment: Power Supply 12-28v, Digital Multimeter (DMM), Frequency Generator,
& Frequency Counter
Test Procedure:
A)
Connect DMM positive lead to power supply positive, connect DMM negative lead to J1-3,
set DMM function to mA DC
B)
Connect power supply negative lead to J1-5
C)
Connect frequency generator positive & negative leads to J1-1,2; respectively. Set output
to sinewave & amplitude to zero
D)
Set S1 for desired frequency range
E)
Turn power supply & frequency generator ‘ON’, DMM should indicate approximately
4.00mA
F)
Adjust ‘ZERO’ (R25) for 4.00mA DMM indication (record data)
G) Set ‘Sensitivity’ adjust (R1) fully clockwise
H)
Adjust signal amplitude of frequency generator to 50mv & frequency to maximum desired
point (full scale frequency) (record data)
I)
Adjust ‘SPAN’ (R19) for 20.00mA DMM indication (record data)
J)
Reduce signal amplitude of frequency generator to zero, adjust ‘ZERO’ (R25) for 4.00mA
DMM indication if necessary
K)
Adjust signal amplitude of frequency generator to 50mv, adjust ‘SPAN’ (R19) for 20.00mA
DMM indication if necessary
L)
Adjust frequency of frequency generator to exactly 50% of maximum frequency point in
step H, DMM should indicate 12.00mA
± .06. Repeat for 25% & 75% full scale
frequencies(record data)
To check linearity @ any frequency point, incorporate the following formula:
(F/F
max
X 16) + 4 = mA
(Where F = Flowrate frequency in Hz)
(F
max
= Frequency in Hz at which 20mA is set)
Ex.
Assume maximum frequency point = 2000 Hz (20.00mA)
Check for linearity @ 750 Hz point
750/2000 = .375
16 X .375 = 6
6 + 4 = 10; DMM should indicate 10.00mA @ 750 Hz input
Power
Supply
12-28 VDC
Frequency
Gen/Ctr
DMM
mA
~
DC
-
-
-
+
+
-
+
5
4
3
2
1