The PKK-312 is a 4-20 mA relay with galvanic isolation.
An intrinsic safety version is available.
The value of input signal is compared with setting value and change of galvanic insulation status, accordingly with the comparison mode in use.

Outputs are configurable according to various applications:

• Switching limit (high or low)
• Control ON/ OFF with setting on switching differential
• Comparative status mode with relay activation or deactivation
• Monitoring of discontinuity or broken loop

Instead of a 4-20 mA a dry contact can be connected to the input.
Status of this contact is copied and the output signal is then galvanically isolated PKK-312 allows the selection of time delays of 0.1; 1; 2; 5 s

Relay status diagram:

Operating modes of relay are programmed through the press buttons on the front, following indications of the LEDs.
One of the most important parameters is the relay operating mode "R":

When current input value is above the threshold:
If R = 1, relay output is activated
If R = 0, relay output is deactivated

Thus, for Drain/Fill or Hold temperature applications, the control mode (normal or reverse) can be assigned to the ON/ OFF function.