rs 485

[Szippijr 0]

I have a pc based system with ptz cameras. I have changed the protocals on the softwar and the cameras but still no movement. I was wondering what screws im to use on the rs 485 adapter? It has five on it. The adapter is plugged into com 1 and the software is set too com one. The cards work awsome in every way except movement. Please Help

[murphomatic 0]

Are the pins labeled? For true RS-485, you'd only use 2 of the pins ..

 

Let me know if they have labels on the pins, and I can tell ya which ones to use..

[Szippijr 0]

tr+,tr-,rxd+,rxd-,gnd,cc

[murphomatic 0]

tr+,tr-,rxd+,rxd-,gnd,cc

rxd+ and rxd- should be the ones you use for your rs-485 +/- leads respectively.

 

Let me know if it works out - or if you've tried this already. Typically 485 runs on the "d" (data) +/- leads... rs-422 would use the four tr/rx leads..

[Szippijr 0]

I have been trying on the t screws. I will have to try that tonight. I hope it works.

[murphomatic 0]

I have been trying on the t screws. I will have to try that tonight. I hope it works.

Did ya get it to work??

[Szippijr 0]

NO, It still wont work and im losing my mind. Tried various protocals and nothing. I have video and i get movement through test mode but nothing through the rs 485. I dunno what the heck to do.HELP

[CollinR 0]

Can you get a make/model of the 232>485 converter?

 

 

You have a RS485 4 wire unit and you need a 2 wire. Many 4 wire units have a dip switch or jumper to put them into 2 wire mode. If you don't flip the switch it'll never work.

[Szippijr 0]

it says hexin on it but i dont see a switch. Is it inside?

[CollinR 0]

I can't find much on that specific converter but others can do the following.

 

Try putting all of the "+" together and all of the "-" together, PTZs don't usually feddabck their position so you shouldn't have data crashes.

[Szippijr 0]

I will try that. I also read in the manual about a 120 resistor

[CollinR 0]

Following the manual (hope it's in English! ) is the best plan.

[Szippijr 0]

No manuel for the rs 485, none for the dvr card but i do have one for the camera. Do I need a seperate control keyboard other than the sofware?

[Szippijr 0]

No Luck, Jumped the wires as directed and nothing. Nothing happens at all. Is the software working with the com port? Do I have a bad 485 adapter? Do I need a seperate ptz controler? Im really confused and hope you guys can walk me thru it.

[kensplace 0]

What does the manual for your cam say?

 

Not got your converter so cant say for sure, but I would normally assume rx is receive and tx is transmit, so the tx + and - on the adapter would go to the rx + and - on the cam. If your cam is full duplex with two way comms then all four may need to be connected (rx to tx, and tx to rx)

 

The 120 ohm resistor is used to terminate the rs485 and is needed on the last device you use, the cam may have a switchable termination resistor (the 120 ohm resistor) or you may need to add one yourself, that part should be explained in the manual.

 

Also, no idea what your cam is, it may be your cam is set up for the wrong protocol, the wrong address, or the wrong baud rate settings etc.

[Szippijr 0]

I have the adress, the protocal and the baud rate correct. It is saying something about the 120 resitor in the camera book. The cam does not have one and i do need to add it. What is it and where do i get one. Thanks

 

 

 

What does the manual for your cam say?

 

Not got your converter so cant say for sure, but I would normally assume rx is receive and tx is transmit, so the tx + and - on the adapter would go to the rx + and - on the cam. If your cam is full duplex with two way comms then all four may need to be connected (rx to tx, and tx to rx)

 

The 120 ohm resistor is used to terminate the rs485 and is needed on the last device you use, the cam may have a switchable termination resistor (the 120 ohm resistor) or you may need to add one yourself, that part should be explained in the manual.

 

Also, no idea what your cam is, it may be your cam is set up for the wrong protocol, the wrong address, or the wrong baud rate settings etc.

[kensplace 0]

Termination resistors are used to balance the signal down the wire, if only a short distance is used, and your baud rate is not too high then you could well find you wont need one. But if you have a longer connection, and or fast baud rate then its more likely you will need to properly terminate the rs485.

 

A google search for rs485 termination will give lots of results on the topic, but basically the 120 ohm resistor is just a small electrical component that can be purchased (very cheaply) from pretty much any decent electronic hobbyist store/catalogue etc that sells electrical components for making circuits.

 

Often equipment has a termination resistor built in, that can be switched in or out of the circuit by a switch, but not always.

 

What model camera are you using? Is there a weblink for a manual for it?

 

Also, try lowering the baud rate if possible to a low value whilst testing, I dont know what you currently have it at, but its easier to get stuff working if you set it fairly low, then up the speed when its all fine.

[Szippijr 0]

I have it set at 9600 now. Its not a popular ptz. It was only 500 bucks or so. Right now i only have about 4 ft of wire from the computer to the camera and only have one wired. I wonder if the adapter is bad or is the wrong one or the pins are in the wrong place. Here is the adapter i have.

 

http://cgi.ebay.com/New-Non-Powered-RS-232-RS-485-Interface-Converter_W0QQitemZ130043352455QQihZ003QQcategoryZ41995QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[kensplace 0]

What are the markings on the pins on the camera end?

 

What is currently connected to what?

 

I have a similar adapter, mine only has 4 pins, (d+/a and d-/b, gnd and 5v) but I managed to get it working with a rs485 telemetry board (after figuring out the darn address settings were marked wrong on the board!) and only used 2 pins the d+/a (going to rx+) and d-/b (going to rx-). I also connected the ground at both ends (cant remember if it worked without the ground, its all in bits at the moment, so cant easily test)

 

Your cam may be marked (if your lucky, I have a dome with no markings on, still trying to figure out what goes where!) with something like one of the above - are there any clues on the cam?

[Szippijr 0]

the cam came pre terminated with screws that say rs 485+ and rs485-.

Im still confused on the pins on the adapter as to wich screws i want., if i need a ground and if i need power. At this point im ready to throw everything away and start over.

[Szippijr 0]

what is a telemetry board? Do i need one of these?

[kensplace 0]

I needed one as I was using a pan/tilt unit and a zoom lens, they didnt have any control electronics, so needed a controller board to control them.

 

If you have a dome camera that supports rs485 and a protocol then it will already have its own telemetry receiver built in.

[Rotten101 0]

from what I understand of two wire systems (such as with your camera) Not only do you have to jumper your T+ with your R+ and your T- with your R- but you also need two 120 ohm resistors one on each end of your bus (your termination lines) Think of it as two wires and on each end you have a 120ohm resistor. Then you connect your signals wires in between the two resistors. The easy way of doing this for one camera is to jump a resistor across the screws for your T+ & T- and across the screws on the camera.