RS-422 / RS-485 Controller or Receiver

[kaysadeya 0]

I plan to experiment with a variety of cheap powered zoom lenses I'm getting from ebay. I have wiring diagrams for the lenses and control of the zoom and focus operations appear to be a simple matter of applying current to one contact or another.

 

My Kodicom DVR appears to provide a PTZ control through an RS-422 connection. Most of the limited information I can gather from the manual relates to expensive off-the-shelf, preconfigured PTZ cameras. Does anyone have suggestions on how to configure a homebrew solution that enables control of zoom/focus through the RS-422 / RS-485 protocol?

 

This is probably a robotics 101 topic, but I'm just getting started on this stuff.

[rory 0]

You're getting deep here

 

Basically you can control it like you would hook up an Alarm Siren on a Relay, where it used power from a seperate Power Supply, and not the alarm Controls Power Supply. The dvr probably has its own alarm relays so you could use them. Im not an expert on relays (havent had time to play with them much yet), but my colleague is, so if you need a hand email me the lens specs and I can pass it by him.

 

I doubt you will be able to use the DVRs PTZ functions as they only normally support certain PTZ manufacturer protocols (ASCII Strings/ Commands) without an external box/receiver of some sought. But for sure you would be able to use the contacts. You may be able to get a protocol like Pelco to work for it as t hat seems to be the most supported protocol in the world .. and has been for years ...

 

Best to check with someone that sells that DVR make though, as well.

 

Rory

[kaysadeya 0]

Right, I'm looking for some sort of external receiver/decoder/controller (aka "box") that translates the rs-422 signals and switches a 9v current to various contacts. I assume there are some very basic boxes out there that do this. I've seen a few boxes on the web and ebay, but it's not completely clear this is what they do. For example:

 

http://www.eaaao.com/choicecycle/78170

 

http://www.securitymax.com/detail.aspx?ID=215

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=5753882332&ssPageName=STRK:MEWA:IT

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=48634&item=5753881487&rd=1&ssPageName=WDVW

[rory 0]

i dont shop ebay so cant help yah there, but ..

 

most Zoom lenses come with or have control boxes .. you may want to find out what brand these lenses are, then go from there.

 

A rat shack relay will work also if hooked up right Just will be controlled via the DVR alarm contact not the PTZ.

 

Rory

[dusan 0]

hi

yes that outdoor model is best universal i seen for your testing

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=48634&item=5753881487&rd=1&ssPageName=WDVW

 

price is 2x more than i like

 

at the moment i use kalatel outdoor ptz box for my testing

 

get one and let as know how it works

 

dusan

[Cooperman 0]

kaysadeya,

 

I'm suddenly thinking sledge hammers and nuts.

 

If you just want to control zoom and focus, would you consider making up your own direct drive box?

 

One switch for (each) lens selection, two switches for zoom and focus, a bit of multicore to each lens, and a plug in regulated power supply unit. If you don't mind messing about with a soldering iron, you could make a controller in a couple of hours. You wouldn't really consider relay drives unless the cable runs were excessive.

 

Just a thought.

[kaysadeya 0]

kaysadeya,

 

I'm suddenly thinking sledge hammers and nuts.

 

If you just want to control zoom and focus, would you consider making up your own direct drive box?

 

One switch for (each) lens selection, two switches for zoom and focus, a bit of multicore to each lens, and a plug in regulated power supply unit. If you don't mind messing about with a soldering iron, you could make a controller in a couple of hours. You wouldn't really consider relay drives unless the cable runs were excessive.

 

Just a thought.

 

Yes, I'd consider this option if I could build a box that accepts the RS-422 signals from my DVR to control the zoom/focus/iris. I don't want to control each zoom with a separate joystick or button combination.

 

If the above is possible, I'd need a clear idea of what components to assemble. I'm not much of a "hardware guy," but not afraid of a little solder. Sounds like you've had some experience in this area. Do you have any pointers to the parts and how to assemble them? Anything to get a kick start would be helpful.

[kaysadeya 0]

hi

yes that outdoor model is best universal i seen for your testing

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=48634&item=5753881487&rd=1&ssPageName=WDVW

 

price is 2x more than i like

 

at the moment i use kalatel outdoor ptz box for my testing

 

get one and let as know how it works

 

dusan

 

Yes, the price seemed high to me too. Do you know where I could get one of these units for around $75?

[Cooperman 0]

kaysadeya,

 

The suggestion for building a 'hardwired' controller, was to try and keep the cost down, not necessarily offer the most "sophisticated" solution.

 

If you want to use the DVR on 422 you will need a suitable protocol convertor, and I personally wouldn't even begin to contemplate building that, if it's possible to pick up an off the shelf adaptor at reasonable cost.

 

I can't suggest any sources off the top of my head, but if I come across anything I think might be suitable, I'll post back.

[kaysadeya 0]

Ok, thanks. I can find a number of cheap hardwired controllers on ebay. Bought a Pelco MLZ6DT I'm waiting to be delivered. From the looks of the wiring diagrams for the controller and zoom lenses, it looks like there won't be any problems. However, my ultimate goal is to be able to control the zooms by means of the DVR remote control from any monitor in the house. I might be able to use the alarm outputs as Rory suggested, but I don't think that would match up with the PTZ controls on the menu. An option might be to remap the PTZ controls to the alarm outputs, but I haven't had the time to dig that deep.

 

There's a lot of information out there on RS-422 and RS-485, but most of it is focused on manipulating digits rather than switching current. Seems like a simple enough task technically; but you wouldn't know that from the prices the CCTV manufacturers charge for their special-branded RS-422 hardware. Either I'm underestimating the challenge or the RS-422 control units are a great profit center for the manufacturers.

[msecure 0]

It's just a matter of buying a RS232-485 Converter & also a multi-protocol decoder board & you can control your PTZ locally or remotely. Total cost below USD120 approximately excluding shipping.

[kaysadeya 0]

It's just a matter of buying a RS232-485 Converter & also a multi-protocol decoder board & you can control your PTZ locally or remotely. Total cost below USD120 approximately excluding shipping.

 

Where?

[bob the b 0]

This will handle the rs232=485 side of things .

 

http://cgi.ebay.co.uk/RS232-to-RS485-conveter-for-CCTV-DVR-and-PTZ-head_W0QQitemZ5799804588QQcategoryZ60839QQrdZ1QQcmdZViewItem

 

These hanle 12v input as i have one so all your connections are in one place.

As for the lens end of things, you have to work out what it requires in terms of power/signal to make it tick.

 

Scour the net for diagrams and pdf's, its all a bit trial and error but you know that anyway

 

Theres loads of odd bits and bobs floating around on ebay for cents that will work in some way.

Good luck

[msecure 0]

Scour the net for diagrams and pdf's, its all a bit trial and error but you know that anyway

 

Theres loads of odd bits and bobs floating around on ebay for cents that will work in some way.

Good luck

 

Not really true! If you have problem with your decoder & the RS232-485 I can give you a hand there. The info that came with what I bought is quite detail! They even mentioned the type of DVR's supported & the right settings for various protocols. Give me a pm kaysadeya if you cannot find what you need & I'll email you my supplier's contact.

[bob the b 0]

I pointed him down the fleabay route as i thought he was attempting a diy job, if you have a box of tricks that will work why not make it public?

 

It could be interesting

[msecure 0]

Not really a box of tricks! The item I bought came with documentation & I just follows. I can scan it to pdf & email it to you guys if you need it. But I cannot promise it'll work with what you have. Well, I'll try to give a short explanation anyway:-

 

PC Side T+, T- goes to decoder board

PTZ & Zoom Lens>Goes into the decoder board (All connections are label), choose the correct settings via the dip switches & that's it!