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Models 415-215 and 425-252 Voltsensors
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
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Description
For process control systems and manufacturing test
equipment, here is a complete Voltsensor system in a single
package—no external components needed, just connect it to
115 VAC for power. These modules contain a DC power
supply, reference voltage, adjustable setpoint, and the output
is a DPDT relay. A LED indicator shows output status. The
relay changes state as the DC input voltage varies around the
set point. Because the unit has its own built-in power supply
and the output is a set of relay contacts, you can apply floating
inputs with voltages of up to 1500V above the AC line neutral.
This isolation makes it feasible to connect ungrounded
thermocouples directly to the amplifier inputs.
Model 425-252
Model 425-252 has a trip range of -14VDC to +14VDC relative
to the module common. Hysteresis is adjustable from 50 mV
to 1 Volt, and sensitivity is 1 mV, so this module should be
used on signals with several volts of amplitude. The input
signal can be floating and the isolation from AC neutral is 500
megohm paralleled by 250 pF. With the latching jumper
removed, the module will latch when the relay goes to the
energized state. The latching state is broken by interrupting
the AC line voltage to the module or momentarily reconnecting
the latch jumper.
Turning the set point adjustment potentiometer clockwise
makes the set point more positive. Turning the hysteresis
adjustment potentiometer clockwise increases the voltage
difference between pull in and drop out.
FIGURE 1-a. Simplified Block Diagram, Model 425-252
Turning the set point adjustment potentiometer clockwise makes
the set point more positive. Turning the hysteresis adjustment
potentiometer clockwise increases the voltage difference between
pull in and drop out.
The modules are epoxy potted for ruggedness and they can
operate over a temperature range of 0° to 50°C. The inputs are
protected against damage due to overvoltage. When you
need an alarm or control circuit in a rugged industrial
environment where ±15VDC power is not readily available,
then these Voltsensors are an excellent choice. Small process
control systems involving temperature control, weighing, and
monitoring can easily be designed using these reliable, low-
cost modules. No complicated wiring, simply connect input
and output with a screwdriver and the control system is ready
to operate.
Model 415-215
Model 415-215 is designed to accept low-level signals, such
as strain-gage bridge outputs and floating thermocouple
signals. Trip point range is ±100mV relative to the module
common. The input signal can have up to ±6V common-mode
voltage relative to module common, and all three input leads
are isolated from ground (500 megohm in parallel with 200
pF). Floating inputs with voltages up to 1500V above the AC
line neutral can be accommodated by this module. Latching
and adjustable hysteresis from 50 µV to 1 mV operate in the
same manner as the 425-252.
FIGURE 1-b. Simplified Block Diagram, Model 415-215