PR181 module in DIN rail enclosure, front three-quarter view

30-240 Ω resistance to 4-20 mA signal conditioner, isolated, with display

Article number PR181-X039

The PR181-X039 converts a two-wire resistance of 30 to 240 Ω into a 4-20 mA signal, for example from a level float or a position sensor. The output is galvanically isolated from the input and the supply to prevent ground loops. Lower and upper limits of input and output are set independently on the display, as is the rise and fall rate of the output. As delivered, 30 Ω on the input gives 4 mA and 240 Ω gives 20 mA.

Supply 9 to 30 V DC
Input two-wire resistance, 30 to 240 Ω, on terminals 3 and 4
Output 4-20 mA as delivered, 21 mA max.; lower and upper limit adjustable

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Specifications

Specifications
Supply	9 to 30 V DC
Input	Two-wire resistance, 30 to 240 Ω, on terminals 3 and 4
Output	4-20 mA as delivered, 21 mA max.; lower and upper limit adjustable
Isolation	Output galvanically isolated from input and supply
Setup	Display with UP, OK and DOWN buttons
Rise and fall rate	Adjustable on the display
Ambient temperature	-25 to 55 °C, non-condensing
Dimensions	45 x 83 mm with DIN rail enclosure, 42.6 x 72 mm without
Factory setting	30 Ω = 4 mA, 240 Ω = 20 mA

Connections

Connections
Terminal	Function
Terminal 1	Supply plus
Terminal 2	Supply minus
Terminal 3	Resistance, common minus, internally connected to terminal 2
Terminal 4	Resistance plus, internally connected to terminal 5
Terminal 5	Not used (internally connected to terminal 4)
Terminal 6	Isolated output common
Terminal 7	Isolated 4-20 mA output (plus)
Terminal 8	Not used

Datasheet (PDF)PDF, 163 kB

Setup

Connect the module according to the terminal table and switch on the supply.
Apply the lowest resistance to the input, for example 30 Ω. In the menu, select IN1 – Set minimum, press OK, select YES and press OK again.
Apply the highest resistance to the input, for example 240 Ω. Select IN1 – Set maximum, press OK, select YES and press OK again.
Set the lower limit of the output with OUT1 minimum adj: change the value with UP and DOWN and confirm with OK.
Set the upper limit of the output in the same way with OUT1 maximum adj.
If required, set the rise and fall rate of the output with Ramp-Up and Ramp-Down.
Setting OUT1 invert to 1 reverses the output: the lowest resistance then gives the highest output level.
Go to the SAVE menu to store the new settings.

Application

Reading fuel level float sensors
Reading position sensors
Driving motors, pumps, valves and hydraulics smoothly with the adjustable rise and fall rate

PR181 series: signal conditioners with display

The modules in the PR181 series are set up on the display on the module, using the UP, DOWN and OK buttons. On most versions the lower and upper limits of input and output are set independently, as is the rise and fall rate of the output; the settings of each module are listed on the product page under Setup. With an adjustable rise and fall rate, motors, pumps, valves and hydraulics can be driven smoothly. On versions with an analogue output, that output is galvanically isolated from input and supply to prevent ground loops. New settings are stored through the SAVE menu. The standard DIN rail enclosure measures 45 x 83 mm (board 42.6 x 72 mm); versions with more terminals are wider. Most modules run on 9 to 30 V DC at -25 to 55 °C, non-condensing.

For some conversions there is also a version without display and without galvanic isolation in the PR100 series: it is set up with push buttons and runs on 12 and 24 V DC (operating range 11 to 30 V DC). Where one exists, it is listed on the product page under Other version.

More about the PR181 series