Wireless RS485 transmission

[RF Lighting]

Hello.

I have a customer who wants to install a PTZ camera on his property.

He wants to be able to control the camera from a keyboard in his house, and have the camera approx 100 - 150 meters away.

The link between the house and the camera needs to be wireless.

I have done this before with video only, but never trying to send RS485 signals the other way to control the dome.

I see this is possible from some googling, but I'm not sure if it's best to use seperate video and data devices or a combined unit.

Also I'm really struggling to find a uk supplier of any wireless RS485 gear.

Any help in deciding which unit is best, and help to source something in the UK would be much appreciated.

 

[Spark123]

DMX is based on RS 485, their wireless thingys are plentiful.

 

[RF Lighting]

Never thought of that. Wonder if it would work ok?

 

[bernardgreen]

Has the customer already bought the camera and PTZ mount ? if not then it would be a lot easier for you that he buys a combined unit, both mount and controller, as the wireless links will be fully compatible with each other. Such systems can include sending camera status to the controller.

Assuming it is only one channel of RS485 then something like this would ( should ) fit the bill

http://www.rfsolutions.co.uk/acatalog/Radio_Modems___Modules.html

they also do good quality video links

http://www.rfsolutions.co.uk/acatalog/Video_Links.html#aX7303

Might be worth putting the question to them in an e-mail.

 

[roasty]

Also Rs485 to rs232 converters and even rs485 to Ethernet (ip) are available. Might be an option to convert to a more commonly used protocol and then transmit that wirelessly?

 

[bernardgreen]

What protocol is being used for the control signals ?.

RS485 is the specification of the physical link. ( the voltage levels etc ). The data can be any format. The PTZ ( pan tilt and zoom ) information may be transmitted as a series of pulse width modulated signals which may not be compatible with a wireless link designed for "normal" serial data transmission.

 

[bernardgreen]

RF lighting

I have sent you a PM.

Regards

Bernard

 

[RF Lighting]

The camera is an existing camera which is being relocated.

The camera control is with a PTZ control keyboard using pelco-D if this is what you mean?

I've found this device on the site bernard linked to. Will this work? Also can I send the PTZ signal via RS232? There seem to be a much greater range of devices for this.

http://www.rfsolutions.co.uk/acatalog/info_TYPHOON_800.html

 

[bernardgreen]

Pelco-D uses a ta format which can be sent by RS232 or RS485.

RS232 was designed for up to 25 metres point to point, computer to modem etc ( single wire )

RS485 was developed for up 100 metres with multiple items on the line in multidrop mode. ( two wire differencial )

Historically cameras were controlled using RS232 over modems and then the introduction of RS485 allowed direct wire connection upto 100 metres ( though it will work over 300 metres ) with RS485 regenerators to extend to several miles

Also can I send the PTZ signal via RS232?

Yes but I would image the control board has RS485 for the pelco-d so a RS485 to RS232 conversion may be needed if the keyboard cannot be configured to send pelco_d as RS232. Conversion back to RS485 may be needed at the camera end. Though the camera may be RS232.

I've found this device on the site bernard linked to. Will this work?

The Typhoon needs to be configure via commands on the serial data. You will need to check if the keyboard can send Hayes commands to set the modem or if text strings can be sent over the RS232 port.

 

[alumni]

RS485 is good for over 1k without mid stream boosters.

 

[bernardgreen]

RS485 is good for over 1k without mid stream boosters.

Only at low data rates and with jitter tolerant receivers.

http://www.maximintegrated.com/app-notes/index.mvp/id/3884

I have seen it over 2 Km with minimal error correction needed.

 

[alumni]

RS485 is good for over 1k without mid stream boosters.

Only at low data rates and with jitter tolerant receivers.

http://www.maximintegrated.com/app-notes/index.mvp/id/3884

I have seen it over 2 Km with minimal error correction needed.

But hardly a problem for this scenario.

 

[EightyTwo]

I think Pelco-D is 4800 baud...

We've used the Verint wireless IP stuff to do this but it can work out expensive to buy and tricky to set up. Their Nextia S1800 series will convert video AND RS485 to IP (and back again).

http://verint.co.uk/solutions/video-situation-intelligence/products/encoders-decoders/index.html

but you'll need some wireless stuff as well...

http://verint.co.uk/solutions/video-situation-intelligence/products/wireless-devices/index.html

...and we used the S4200 at 5GHz. Line of sight is pretty important

 

[alumni]

Another option could be the Videowave range from RDT

http://www.radiodata.co.uk/products/wireless-video/videowave-analogue-58ghz