TWN-FO and TWI-FO - PLC Input Transmitter:

Product Specifications:

Download Installation Guide



The TWI-FO and TWN-FO are designed as a low cost alternative to expensive A/D cards on PLC's, computers and data acquisition systems.
The TWI-FO and TWN-FO convert and analogue signal into a linear, frequency output signal, with a 50:50 mark space ratio. Ideally designed to be used with a PLC to convert a 4~20mA signal into a 10~1010Hz frequency, (Other calibrations available.) allowing direct connection into a digital input on a PLC (Use with interrupts.) and powered by the PLC's 24Vdc power supply. Refer to 'Connection Diagrams' for the multiple connection variations.

Note: The conversion from TWN-FO to TWI-FO is easily achieved by the removal of two internal links. Refer to ranging information.


  • PLC Interface. Converts 4~20mA Signal into a Frequency for Direct Conversion into a Digital Input.
  • Isolated Input to Output 1.6kV for TWI-FO.
  • High Accuracy.
  • LED Indication of Frequency Output.
  • Low Cost.
  • Easy to Install.
  • Compact DIN Rail Mount Enclosure.
  • Reverse Polarity Protection.
  • Externally Accessible Span and Zero Adjustments.

Ordering Information:

TWN-FO ordering table


TWN-FO specifications