Red Lion CUB4V - Manual (Page 4)

TYPICAL VOLT & CURRENT MEASUREMENT APPLICATIONS
CURRENT METER SCALING
The CUB4 Current Meter display can be scaled to almost any lower
numerical value. Setting the Scale switch to the “ON” position enables the
Scale Potentiometer, which is used with the current range selection jumper to
scale the unit. The Scale potentiometer can be set to divide the normal current
reading by a division factor between 1 and 13.
EXAMPLE: The CUB4 Current Meter has been connected to measure a circuit
current to 120.0 mA maximum. However, in this application, the display is to
indicate percent of load current with 120.0 mA equivalent to 100.0 percent.
The scale potentiometer is adjusted to reduce the normal 120.0 mA signal input
display reading of 120.0 to indicate the desired reading of 100.0 on the display.
Scaling to obtain a numerical readout higher than the normal value of the
current can also be accomplished in most cases by selecting a lower current
range. However, the maximum current for the range must not be exceeded.
(See Specifications for maximum input currents.)
VOLTMETER APPLICATION
Indicating the Speed of a D.C. Motor
A foreman in a plant wants to get a more accurate indication of the speed at
which a variable speed DC motor drive is operating. The only indication he has
now is the position of a dial on the control panel.
The motor has a tachometer generator that will output a 10 VDC signal when
the motor is running at its maximum speed of 1800 RPM. The power supply of
the control has a 15 VDC output that can supply power to
the CUB4V.
Since this application requires a non-standard readout, it will be necessary to
scale the display. The Scale DIP switch is set to the “ON” position to enable the
Scale Potentiometer. The Division Factor is calculated using the formula:
D.F. = (Maximum output) x D.D.P.
(Desired Display)
D.F. = 10 x 1000
1800
D.F. = 5.5
Since the division factor falls between 1.2 and 10.5, DIP switch position S2 is
set to the “ON” position, according to the Division Factor Selection Chart.
To scale the CUB4 Voltmeter, the motor is run at full speed and a calibrated
photo tachometer is used to obtain the exact speed. The Scale Potentiometer on
the CUB4 Voltmeter is then adjusted until the display reading agrees with the
tachometer. Alternately, the output of a precision voltage source set to +10 VDC
can be connected to the signal input of the unit and then adjust the scaling
potentiometer for the desired reading.
CURRENT METER APPLICATION
Analog Meter Replacement
A manufacturer wants to replace several 1 mA DC analog meter movements
with easy to read CUB4 Current Meters with backlighting. One application
involves measuring the flow rate of a liquid to indicate 0 to 250 gallons per
minute.
Since 1 mA of current flow requires a display reading of 250, the CUB4
Current Meter will need to be scaled. The Scale DIP switch is set to the “ON”
position enabling the Scale Potentiometer. The proper current range for the
application is then selected. The Scale potentiometer will divide the display
reading by 1 to 13, for the particular current range selected. A reading of 250 is
4 times less than the normal reading at 1 mA for the 0 to 1.999 mA range,
therefore the jumper is installed in the 0-1.999 mA range position. No decimal
point is selected because the resolution is 1 gallon.
The CUB4 Current Meter can now be scaled. Apply 1 mA to the signal input
and adjust the scale potentiometer to the desired reading.
TROUBLESHOOTING
For further technical assistance, contact technical support at the appropriate
company numbers listed.
GENERATOR
TACHOMETER
-
+
MOTOR
SUPPLY
POWER
SIGNAL IN
+
GND (COMMON)
+VD
C
8 7 6 5 4 3 2 1
1 COM ON
3 SIG.+
M1508F
CUB4V
0.00 0.000 SCAL
E
0.
0
SCAL
E
CALIB
.
19.99VDC 199.9m
V
1.999VDC 199.9VDC
7
MADE IN U.S.A.
RED LION CONTROLS
YORK, PA.
3 1 2 5 6 4 8
D.P.
V+ 2
1 2 3 4
POWER
SUPPLY
FLOW
+VD
C
SIGNAL IN
+
COMMON
SIGNAL IN
-
YORK, PA.
RED LION CONTROLS
3 SIG.-
1 COM
1.999mA
199.9uA
SCAL
E
ON
1
0.00 0.000
3
0.
0
2 4
199.9mA
19.99mA
MADE IN U.S.A.
CALIB. SCAL
E
V+ 2
CUB4I
SIG.+ 4
BLOCK DIAGRAM CUB4I
Red Lion Controls
Headquarters
20 Willow Springs Circle
York PA 17406
Tel +1 (717) 767-6511
Fax +1 (717) 764-0839
Red Lion Controls
China
Unit 302, XinAn Plaza
Building 13, No.99 Tianzhou Road
ShangHai, P.R. China 200223
Tel +86 21 6113 3688
Fax +86 21 6113 3683
Red Lion Controls
Europe
Softwareweg 9
NL - 3821 BN Amersfoort
Tel +31 (0) 334 723 225
Fax +31 (0) 334 893 793
Red Lion Controls
India
201-B, 2nd Floor, Park Centra
Opp 32 Mile Stone, Sector-30
Gurgaon-122002 Haryana, India
Tel +91 984 487 0503