OPEN LINE DETECTOR

[rembrandt_76]

Hi Guys!

Just want to ask your suggestion/ideas on how I can monitor if one of my line connections is open or not. This line is an interconnection between two active devices. The first device sends a pulse signal to the second device and vice versa. I want to make a device/circuit such that I will be able to know if this line is disconnected.

Appreciate your suggestions. Thanks.

Rembrandt :?

 

[Nigel Goodwin]

Just want to ask your suggestion/ideas on how I can monitor if one of my line connections is open or not. This line is an interconnection between two active devices. The first device sends a pulse signal to the second device and vice versa. I want to make a device/circuit such that I will be able to know if this line is disconnected.

There's far too little information, you need to explain exactly what you want, and provide a circuit diagram.

 

[rembrandt_76]

Hi,

I am attaching a file to explain the operation of the system and the solution I am looking for. Thank you for your interest to help.

Regards.

 

[Nigel Goodwin]

I don't see as it's possible as presented, obviously the lines can be either high or low depending on the signal - so there's nothing you can check there.

Are the two systems microcontrollers?, and are you writing the software for them?.

By having a pullup resistor on the receive side of each line, and holding all the output lines low, you could check that the receive side lines are all low - a break in any wire would result in that line going high.

Or you could send each data packet twice, with the second one inverted, like this - '0010' then '1101'. You could then detect any faulty lines.

Or you could send send pulses on each line, where one type of pulse is a zero, and another type of pulse is a one (using either different frequencies or mark/space ratios) - obviously a missing pulse would signify a broken line.

A lot really depends on what's happening, and how fast it needs to work, plus what control you've got over it all!.

 

[ConKbot of Doom]

You could do something like make every 10th byte (or nybble in the case of the drawing) is all ones. Both devices should know which bit is the 10th, so when the second one dosen't see all ones, it sets off the alarm.

 

[IRQ57]

Controllig data transm.

Hi Rembrand,

Another way is to generate at the output a fifth line ,known as "parity". It may be odd or even so every time a group of bits appear in the output, a logic circuit generates or not a bit, to make a total of bits odd or even. If a line opens, it will be detected in the receiver and a sixth line will send in response an error signal, otherwise this line will stay inactive.

Regards