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

PWM to relay with adjustable threshold, isolated, with display

Article number PR181-X055

The PR181-X055 reads a PWM signal and switches a relay as soon as the signal stays above the threshold for longer than a set time. The threshold and the minimum duration are set on the display, so the relay does not chatter when the signal hovers around the threshold for a long time. The input is galvanically isolated from the supply and therefore reads PWM signals that are high-side or low-side switched. A DIP switch selects a PWM level of 3.3, 5, 12 or 24 V; as delivered, the module is set to 12 V.

Supply 9 to 30 V DC
Input PWM, 3.3, 5, 12 or 24 V, on terminals 3 (minus) and 4 (plus); high-side or low-side switched
Output relay with changeover contact (NO, COM, NC)

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Specifications

Specifications
Supply	9 to 30 V DC
Input	PWM, 3.3, 5, 12 or 24 V, on terminals 3 (minus) and 4 (plus); high-side or low-side switched
Output	Relay with changeover contact (NO, COM, NC)
Isolation	Input and output galvanically isolated from each other and from the supply
Setup	Display with UP, OK and DOWN buttons; PWM level with DIP switches S1 and S2
Input frequency	100 Hz to 5 kHz
Threshold	Adjustable, with a minimum duration above the threshold in milliseconds
Relay contact voltage	24 V DC max.
Relay contact current	5 A DC max.
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	Input set for a 12 V PWM signal

Connections

Connections
Terminal	Function
Terminal 1	Supply plus
Terminal 2	Supply minus
Terminal 3	PWM input minus (-)
Terminal 4	PWM input plus (+)
Terminal 5	Not used
Terminal 6	Relay contact, normally open (NO)
Terminal 7	Relay contact, common (COM)
Terminal 8	Relay contact, normally closed (NC)

Datasheet (PDF)PDF, 148 kB

Setup

Select the PWM signal level with DIP switches S1 and S2: 24 V = S1 off, S2 off; 12 V = S1 off, S2 on; 5 V = S1 on, S2 off; 3.3 V = S1 on, S2 on. Only change the DIP switches with the input signal disconnected, to avoid damaging the module.
Connect the module according to the terminal table and switch on the supply.
Set the input to the required threshold, for example 50 % duty cycle. In the menu, select IN1 – Set trig, select YES and confirm with OK.
Use IN1 trig time adj to set how many milliseconds the input must at least stay above the threshold before the relay switches: change the value with UP and DOWN and confirm with OK.
Fine adjustment: IN1 – trig adj adjusts the threshold.
Go to the SAVE menu to store the new settings.

Application

Switching a relay as soon as a PWM signal exceeds a threshold, without chattering around the threshold
Reading PWM signals of 3.3 to 24 V, high-side or low-side switched

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