How can we help you today?

Why TesysT logic inputs are unexpectedly activated if nobody activated pushbutton connected to logic input?

It can happen due to very long cables connected to a logic input. This problem is more frequent in the case of AC signal than DC signal. Long cables (over 50m) have a capacitance that is significant enough for flowing the leakage current that can unintentionally activate TEsysT logic input.
Solution:
Use shorter cables
Use LTMR...BD instead of LTMR..FM. DC signal has a lower leakage current than AC.
Use interposing relay. The coil of the interposing relay has a lower impedance than the TEsysT logic input and so a greater current in the connected signal cable is needed to energize the relay. A push button installed far away will activate the relay (the relay must be close to TEsysT) and contact from the relay will activate LTMR logic input.
Add a resistor to each LTMR logic input.

Schneider Electric Philippines

Attachment(s)
Special_case_Long_lines_AC.pdf [642.13 KB]
Explore more
Range:
Users group

Discuss this topic with experts

Visit our community and get advice from experts and peers on this topic and more
Explore more
Range:

Need help?

Need help?

Product Selector

Product Selector

Quickly and easily find the right products and accessories for your applications.

Get a Quote

Get a Quote

Start your sales inquiry online and an expert will connect with you.

Where to buy?

Where to buy?

Easily find the nearest Schneider Electric distributor in your location.

Help Center

Help Center

Find support resources for all your needs, in one place.

  • Products Documentation
  • Software Downloads
  • Product Selector
  • Product Substitution and Replacement
  • Help and Contact Center
  • Find our Offices
  • Get a Quote
  • Where to buy
  • Schneider Electric Community
  • Careers
  • Company Profile
  • Report a misconduct
  • Accessibility
  • Newsroom
  • Investors
  • EcoStruxure
  • Job Search
  • Blog
  • Privacy Policy
  • Cookie Notice
  • Terms of use
  • Change your cookie settings