RS-485 splicing

[mikefamig]

If the clamping voltage is too close to the operating voltage, the MOV may conduct under normal operation, which would do two things.  On a data bus, it would short the data signal to ground, corrupting the data and causing errors. Each time the MOV conducts, it will use up some of its protection ability and service life, and eventually will fail.  And if you do get a real surge before the MOV totally fails, the MOV may no longer be able to dissipate as much as it is supposed to.

OK this makes me even more comfortable with 22 volt clamping. I bought two new Ditek 4lvlpx for ten dollars each on Ebay and was having second thoughts about using them but now I think that I did well. I hope that we don't have any thunder snow storms, I probably won't install these until we get a warm day in the springtime.
 
One more question, what is the significance of the 18 volt max continuous operating voltage on this device?
 
Mike.

 

[RAL]

One more question, what is the significance of the 18 volt max continuous operating voltage on this device?

 
 
The maximum continuous operating voltage (MCOV) is the highest voltage that you can subject it to without degrading the capabilities of the MOVs.  So the 18V rating on the Ditek gives you a little headroom over the 12 to14V that the RS-485 bus is likely to see.

 

[mikefamig]

If the clamping voltage is too close to the operating voltage, the MOV may conduct under normal operation, which would do two things.  On a data bus, it would short the data signal to ground, corrupting the data and causing errors. Each time the MOV conducts, it will use up some of its protection ability and service life, and eventually will fail.  And if you do get a real surge before the MOV totally fails, the MOV may no longer be able to dissipate as much as it is supposed to.

 
Very good, I think that maybe a 16 volt continuous operating and 18 volt clamp would be ideal but I like the 18/22 fine.
 
You should be a teacher!  (assuming you are not)
 
Mike.

 

[mikefamig]

I finally found a link with detailed specifications for the Ditek  lvlp-x. It even states straight out that it is recommended for alram panels.
 
http://www.applied-computer.com/Inventories/TechnoteDetail.aspx?Acpn=000000&GroupID=4817212
 
Mike.

 

[RAL]

You should be a teacher!  (assuming you are not)

 
Thanks for the compliment!
 
Although I don't consider myself a professional educator, back 30+ years ago, I did work as an adjunct professor at two local colleges for a few years.  Also taught programming to kids in an eagle scout troop.  Working with the kids taught me that it's very easy to take very basic things that you know for granted and assume that everyone knows them.  That got me in the habit of explaining things in much more detail (sometimes too much   )

 

[mikefamig]

Thanks for the compliment!
 
Although I don't consider myself a professional educator, back 30+ years ago, I did work as an adjunct professor at two local colleges for a few years.  Also taught programming to kids in an eagle scout troop.  Working with the kids taught me that it's very easy to take very basic things that you know for granted and assume that everyone knows them.  That got me in the habit of explaining things in much more detail (sometimes too much   )

Works for me, you are very good at conveying your thought in writing which is not to be taken for granted. I majored in business data processing back in school days and attended a course on technical writing which was enlightening and has no doubt helped me both writing and reading at a tech level through the years.
 
Over time I've done a lot of tutoring of friends and family of general care and use of their pc and often start by saying "I don't mean to talk down to you but I don't know how much you do and don't already know" Some people are impatient and/or insulted when you start telling them things they already know. Then others are a blank slate and you have to start at a very fundamental level. Me - I'm kinda addicted to learning and it's hard to insult me. If you're willing to share then I'm more than happy to listen.
 
Mike.

 

[mikefamig]

BTW guys - I've had a squeaky clean log file and no abnormal behavior since I replaced the rs485 crimp connectors with soldered splices. For a while I thought hat I'd never pinpoint that problem

 
Well I spoke too soon.
 
On New Year's Eve just a day after posting that the system has been running well I had another auto restart. After restarting, all of the zones in both areas report as bypassed as opposed to in the past when it was only the xin zones in area2 that would bypass after the restart.
 
I am going to start a new thread to see if I can find anyone else seeing restarts in their event log.
 
Mike.

 

[Del91574]

You have FA on the zones? Is it for devices just on the XIN's or panel also? Panel disarmed or armed at the time? Did it occur more than once?
 
Going to point towards the media; most likely it's copper related on the bus and not the panel.
 
There is a known bug on the KP FW that is unrelated, 100% doubtful that is an issue.

 

[mikefamig]

You have FA on the zones? Is it for devices just on the XIN's or panel also? Panel disarmed or armed at the time? Did it occur more than once?
 
Going to point towards the media; most likely it's copper related on the bus and not the panel.
 
There is a known bug on the KP FW that is unrelated, 100% doubtful that is an issue.

 
Both areas were armed but there was no false alarm.The log shows the start up and then shows one log entry for each zone being bypassed in sequence. All zones in both buildings/areas were affected and bypassed. Then the system resumed normal armed operation.

 

[Del91574]

So the system had the zones bypassed and then the bypasses cleared with the system armed? Reading the log it looks like the panel rebooted but you would need to determine why.

Sounds like something PTC related might have kicked out the panel's aux power and reset/cleared.

 

[mikefamig]

So the system had the zones bypassed and then the bypasses cleared with the system armed? Reading the log it looks like the panel rebooted but you would need to determine why.

Sounds like something PTC related might have kicked out the panel's aux power and reset/cleared

The event log shows each zone bypassed but I didn't check to see if they really were armed or bypassed when I got home. The alarm still appeared to be armed and I disarmed it before entering the house.
 
I understand that the M1 re started. I would love to determine why it re started But why does the log show that the zones were bypassed? They are not even set as being by passable in RP.
 
Mike.

 

[Del91574]

I just tried a couple of things on mine for giggles. I armed the system (night) and let it do it's course. Bypassed a few zones, put them back as normal and pulled the log.
 
Shows arming, bypassing but no return. I think the system will only log security global operations or items that negate the system and make it less secure. Most systems operate the same. They only care if the system is armed/disarmed or if someone negates a portion of the system (bypass or force arm) not whether or not they return back to normal system operation.
 
Guessing your reboot caused the system to bypass the points until they stabilized and the system was able to process their normal state vs. alarm state and were probably functioning fine.
 
I'm guessing the panel's aux power kicked off (barely) and the PTC cooled down reasonably quickly without the load. Why, I can't say, but I'd look to whatever load is connected to the panel's aux power terminals possibly shorting out.

 

[mikefamig]

I just tried a couple of things on mine for giggles. I armed the system (night) and let it do it's course. Bypassed a few zones, put them back as normal and pulled the log.
 
Shows arming, bypassing but no return. I think the system will only log security global operations or items that negate the system and make it less secure. Most systems operate the same. They only care if the system is armed/disarmed or if someone negates a portion of the system (bypass or force arm) not whether or not they return back to normal system operation.

 
That all makes a lot of sense, you have insight that comes from experience.
 

Guessing your reboot caused the system to bypass the points until they stabilized and the system was able to process their normal state vs. alarm state and were probably functioning fine.
 
I'm guessing the panel's aux power kicked off (barely) and the PTC cooled down reasonably quickly without the load. Why, I can't say, but I'd look to whatever load is connected to the panel's aux power terminals possibly shorting out.

 
 The ethernet expander is the only thing powered by the vaux and I will take a good look at the connection tomorrow. The Altronix powers only the garage xin zones so I would only expect to see those zones reset if the fault was there. It may make sense for the vaux power supply on the M1 control to maybe reset the control board causing all zones local and remote to reset.
 
Mike.

 

[Neurorad]

Just came across this new Wago 221 lever lock connector, smaller and clear

Pdf download of sell sheet
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