Martel Electronics SP200 - Manual (Page 4)

SP 200
3½ Digit Backlit LCD Voltmeter Module
Specifications liable to change without prior warning SP 200 Issue 3 October/2001 M.C. Applies to SP 200/1
V+
V+
INH
INL
0V
GND
+
-
±200mV
RI
RO
Measuring a single ended input
voltage referenced to supply, i.e. the
input voltage and the meter's power
supply share the same 0V rail.
V+
V+
INH
INL
COM
0V
GND
+
-
±200mV
RI
RO
Measuring an input voltage referenced to
a floating supply, i.e. the input voltage
and the meter's power supply are isolated
from each other. Measuring a 4-20mA loop current.
The meter's power supply must be isolated
from the 4-20mA current loop.
V+
V+
5k
220k
R
INH
INL
Set Zero
COM
0V
GND
I +
I -
4-20mA
RI
RO
R= Reading at 20mA
160
APPLICATIONS
Do not connect more than one meter to the same power supply if the meters cannot use the same signal
ground. Taking any input beyond the power supply rails will damage the meter.
Measuring supply voltage and current to a load.
Display DP1, DP2 or DP3 by connecting to GND, as required.
RI
RO
COM
INH
+5V
Load
Shunt
R
L
V+
V
A
S
1
INL
GND
Rs
7805
220nF 470nF
10uF V
supply
I
Ra=1M
Rb=1k S selects between voltage and current display.
1
Ra and Rb shown scaled for 200V .
Rs = 200mV (e.g. 0.1
for 2A range)
FSR
Ω
I
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SCALING
Two resistors Ra and Rb
may be used to alter the
full scale reading (FSR) of
the meter - see table. The
meter will have to be re-
calibrated by adjusting the
calibration potentiometer
on the rear of the module.
FSR Ra Rb
2V 910k 100k
20V 1M 10k
Vin 200V 1M 1k
2000V* 1M 100R
200 A 0R 1k
2mA 0R 100R
in 20mA 0R 10R
200mA 0R 1R
µ
I
Voltage
Current
+
-
Ra
Rb
INH
11
12
Vin or in I
INL
SP 200
Page 4 of 4
*Ensure that Ra is rated for high voltage use.
www.lascarelectronics.com
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PO Box 770, Londonderry, NH 03053 1-800-821-0023
www.martelcorp.com