A
Models 4900, 4901 and 4902 DC Transmitters
Manufacturing Company, Inc. Concord, California 94520 Ph: 925/687-4411 or 800/542-3355 Fax: 925/687-3333 www.calex.com Email: sales@calex.com
1
Model 4902 Block Diagram
AC POWER
Model 4900 Block Diagram
Model 4901 Block Diagram
AC POWER
AC POWER
Features
!
0 to +10V Input and 4-20mA Output
4-20mA Input and 0 to +10V Output
0 to +10V Input and +1 to +5 Output
!
1500 Volts RMS of CMV Isolation
!
Factory Calibrated for Accuracy of 0.1%
!
Operates from 115VAC 50/60Hz or 230VAC
!
Rugged Epoxy Encapsulated Design
Description
The CALEX 4900 series Transmitters isolate the input from
the output and the power line. These units are ideal for
eliminating ground loops and common mode signals. For the
4901, which converts 4-20 mA to 0 to 10V, the input resistance
is less than 50 ohms generating less than 1 Volt loop voltage
at 20mA loop current. For all models, the 400Hz frequency
response provides a settling time of less than 0.003 seconds
to 0.1% which will prevent signal degradation. Power line
related noise is less than 0.03% P-P of the span.
The 4900 Isolators are factory calibrated for accuracy of 0.1%
of span. ZERO and SPAN potentiometer access is provided
for field fine tuning if required. With the 4901, these adjustments
are easily made by supplying a known 4mA input current and
adjusting the ZERO potentiometer for zero Volts output. The
span is then adjusted for +10 Volts output with a full scale input
of 20mA. This procedure should be repeated due to some
interaction between the adjustments. The Model 4901 output
will go to a negative 2.5 Volts with zero input current, providing
a positive indication of the current loop integrity. The 4900 is
adjusted by first shorting the inputs together, pins 8 and 9,
adjusting the ZERO for 4mA output. Then apply 10 Volts to the
input and adjust the SPAN for 20mA output.
These models are completely encapsulated for use in rugged
environments. They are similarly protected against shock and
vibration for years of reliable and accurate operation. All
connections are easily made to conveniently located barrier
strips. The 4900 series operates on 115 Volts 50/60 Hz and is
available for 230 Volt line operation.
A
Models 4900, 4901 and 4902 DC Transmitters
Manufacturing Company, Inc. Concord, California 94520 Ph: 925/687-4411 or 800/542-3355 Fax: 925/687-3333 www.calex.com Email: sales@calex.com
2
SIDE VIEW
4900 Series Specifications
TOP VIEW
Mechanical Specifications
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