Elk Data Bus - Recommended Surge Protection

[gatchel]

I wanted to post to see if there is an Elk recommended surge suppressor for the RS485 Data Bus.

I have a garage that will be on line soon and would like to install a surge protector at each point of entry on the house and the garage. I was thinking of using a Ditek device.

Is there a recommended unit?

If not, what is the recommended clamping voltage for the RS485 bus?


Thank you

 

[gatchel]

bump

 

[gatchel]

Well. What has been said in this post thus far is also what I could get on the phone from Elk. I am very surprised that they can't recommend a brand or any specifics. The guy on the phone sounded very, very new..

If any one else has used any products with the ELk stuff your input will be greatly appreciated. Otherwise I guess I am on my own on this one.

 

[andygee]

Well. What has been said in this post thus far is also what I could get on the phone from Elk. I am very surprised that they can't recommend a brand or any specifics. The guy on the phone sounded very, very new..

If any one else has used any products with the ELk stuff your input will be greatly appreciated. Otherwise I guess I am on my own on this one.

I'm in the same boat as you, but everyone that I've talked to has really recommended the Ditek devices. I've got a couple of them on order and can let you know how they are once I get them.

Andy

 

[gatchel]

I also have used numerous ditek devices out in the field. What I thought was a simple question turned out to be a disappointment as far as Elk's help. I know the power on the data bus is 12vdc, that's easy. The issue is,... does the data bus really follow the RS-485 Spec, 100%? I have seen manufacturers that don't and call it RS485. If so, I can gather data and make the choice based on the RS485 spec alone. I am surprised that Elk doesn't make a unit or have a recommended one to buy.

Let me know how you make out.

Thanks

 

[JimS]

RS-485 is usually 0 to 5 volt levels. There are a couple ways to check this out.

1. Measure the voltage on the data lines. You could use an oscilloscope but most people don't have one. Try using a multimeter to measure from the ground line to each data line. If no data is being sent one line should be high and one low. That should tell you the voltage. Not sure if the Elk has inactive periods long enough for this to work well. If not you could take a diode and small capacitor with the meter to measure the peak of the pulses.

2. Look at the numbers on the RS485 drivers if the board is open. Then look up the data sheet of the part.

Most common 5V chips have an absolute maximum rating of 7 V. A lot of RS485 chips have a 12V max (if I remember correctly). Some have up to 60V withstand ratings. If the chips are in sockets (not likely) you could put in a chip with higher ratings.

I agree that Elk should be able to tell you more about this.

 

[gatchel]

Jim

Thanks for the feedback. I didn't think of checking out the chip specs. That's a good idea.

 

[gatchel]

The Elk P212S has a SP485EC chip on it. It's a Sipex RS485 driver chip. The driver output says ± 15V.

Here is the data sheet if anyone else is interested:

http://pdf1.alldatasheet.net/datasheet-pdf/view/45952/SIPEX/SP485ECN.html

I'll check the other devices later.

 

[gcimmino]

Howdy all. Long time no post. I called Elk TS once on this topic a long while ago. Didn't get much of a satisfying answer either.

That said, have you looked at the Elk-950 "Telephone & Power Line Surge Suppressor"? What, not intuitive you say?

From the install guide:

The POWER terminals may alternately be used for surge protecting data transmission wires such as a
keypad or zone expansion bus, as long as any measurable voltage on the two data wires is less than 24 volts.
Connect the data wires to the IN and OUT terminals while observing polarity using the A & B markings.

I'm just about to install a pair on either side of a data bus that runs between two buildings.

 

[gatchel]

Howdy all. Long time no post. I called Elk TS once on this topic a long while ago. Didn't get much of a satisfying answer either.

That said, have you looked at the Elk-950 "Telephone & Power Line Surge Suppressor"? What, not intuitive you say?

From the install guide:



I'm just about to install a pair on either side of a data bus that runs between two buildings.

Wow...Good find. The fact that Elk couldn't tell me that is really really frustrating and also very disappointing. I guess the days of the excellent support cocooners are used to are dwindling...or gone for good. Maybe it's good because they have been busy with new products. Let's hope that's the reasoning.

Anyway...I have decided after some fact finding to go with Ditek surge suppression as I have used with many other products in the past. I have decided on either DTK-2LVLP-X or DTK-2MHLP!@B-WB devices. The clamping voltage is around 18v on these devices. As long as the Elk RS-485 follows the true RS-485 spec we should be good to go. I will let you know how things work out.


Did I mention how frustrating it is that "Tech Support" didn't even have a clue...So far It sounds like Elk support is still Based in the USA :lol: :rofl:

That's a good thing.

 

[tmbrown97]

Along this same topic, I stumbled across this stuff last night - I wonder if it'd help with those more exposed runs...

http://www.ubnt.com/toughcable