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Manufacturer of computer controlled relay, I/O and custom boards for commercial and industrial applications.

Please Note: Pencom will be closed from September 12th thru September 23 - we will re-open on September 26

** Please note supply chain shortage update 09-07-2022 -  a limited supply of the backordered parts will be arriving around September 28th for the USB boards - more parts are on order:   We have many backordered boards that will be produced first - notifications will go out to customers to verify the orders are still valid.

There will be production delays due the volume of the backorders

Due to the supply chain shortages we have been having a difficult time obtaining parts to produce our products.  Some of our parts have been on order for 12 months  Some parts are being received for certain products and we will do our best to fulfill what we can.

In addition we have been experiencing problems with our email system and many emails were never received on the following accounts our and, this has been happening for some time and we were unaware since it is happening sporadically. 

We have created two new accounts to use until we can determine the problems we are having with our system and please use these emails to contact us.

Other email address have been the same problems and we will work to correct these too.


AC Voltage line monitor 120/240VAC 50/60/400Hz

This image is an example for illustrative purposes only and may not be the exact part number of this product.
Production for RoHs units require at least a week to produce.
Typically a 2-3 Day Production <10pcs
Our quantity discounts:
Quantity 5+ 25+
Price $30.27 $28.67
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Optically isolated AC line voltage monitor circuit board to TTL logic output. This board is used to detect when the line voltage is active or failed, can also be used for ON/OFF sensing applications as a closed loop monitor for relay contacts, motors, or as a fuse monitor.  Output is 5VDC TTL logic.

Standalone operation, logic output of 5VDC will work with most boards with an input port or microprocessor with 5V tolerant inputs.  Requires a regulated 5VDC power source to power the circuits on the board.

Note: 2 of these units may be operated from our relay boards or any of our boards with the 8 channel I/O port option.  The boards can be powered by the VCC (+5VDC) and ground connections on these ports, no external power supply required when connected to our units.

Nominal line voltage is 120/240VAC 50/60/400Hz, Voltage tolerance: minimum 81VAC to maximum 252VAC.  Will also detect DC voltages within this range.

1 - Detect AC line failure 50/60/400Hz (can also detect lower frequencies and high voltage DC ON/OFF sensing applications)
2 - Closed loop detector to monitor relay contacts, solenoids, motors, etc.
3 - Fuse or circuit breaker monitor
4 - Monitor ON/OFF AC/DC operation in remote locations, detect when a device is activated or deactivated locally

AC/DC line monitor example wiring

AC line monitor specifications and options (AC_line_monitor_datasheet.pdf, 435 Kb) [Download]

AC line monitor instruction manual (AC_Line_Monitor_Instruction_Manual.pdf, 381 Kb) [Download]

AC line monitor board layout (AC_Line_Monitor_Board_Layout.pdf, 62 Kb) [Download]

AC line monitor board drill template (AC_Line_Monitor_Board_Drill_Template.pdf, 51 Kb) [Download]

AC line monitor part number format (AC_Line_Monitor_Part_Number_Format.pdf, 82 Kb) [Download]

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Hardware mounting kit