PTZ wiring questions

[Bluzman23 0]

Hi,

Just looking for some help on typical ptz Rs-485 wiring.

I currently have 1 PTZ camera installed and have it directly wired to my Everfocus DVR. I can control the basics thru the dvr, pan, tilt, zoom, iris. But have no tour or preset type controls. I am considering purchasing a joystick controller for it to give me more ease of use. My questions for now are 1. If I add aditional ptz cameras to my setup dio I need to run a homerun to each for ptz control from the dvr/ controller to the cam, or do I daisy chain them from one cam to the next with only 1 pair ending at the dvr/controller ?

2. when using a single or multiple ptz cameras do I need an EOL (end of line) resister.

3. are there any specs I should be looking for when searching out joystick controllers or are most the same. I have been looking at controllers with LCD displays on them.

 

Right now I have a Chineese model Ptz installed with plans of adding a CNDB-100 which I alredy own.

 

Any help would be great.

[survtech 0]

Hi,

Just looking for some help on typical ptz Rs-485 wiring.

I currently have 1 PTZ camera installed and have it directly wired to my Everfocus DVR. I can control the basics thru the dvr, pan, tilt, zoom, iris. But have no tour or preset type controls. I am considering purchasing a joystick controller for it to give me more ease of use. My questions for now are 1. If I add aditional ptz cameras to my setup dio I need to run a homerun to each for ptz control from the dvr/ controller to the cam, or do I daisy chain them from one cam to the next with only 1 pair ending at the dvr/controller ?

2. when using a single or multiple ptz cameras do I need an EOL (end of line) resister.

3. are there any specs I should be looking for when searching out joystick controllers or are most the same. I have been looking at controllers with LCD displays on them.

 

Right now I have a Chineese model Ptz installed with plans of adding a CNDB-100 which I alredy own.

 

Any help would be great.

I'm not familiar with Everfocus DVRs but whether you need to homerun multiple PTZs depends on your controller. You can daisy-chain PTZs if the controller has the ability to handle multiple addresses per port. If it does, you would set one PTZ to address "1"; the second to address "2" and so on; then set up the address perimeters in the DVR or controller.

 

When you daisy-chain multiple RS422/485 devices, it is recommended to turn termination "off" on all but the last device in the chain but we typically daisy-chain up to three PTZs and leave them all terminated with no problems. The resulting load on the transmitter (DVR or joystick) would be:

1 device - 100 ohms

2 devices - 50 ohms

3 devices - 33 ohms.

 

I was talking to the owner of Sennetech (a code converter manufacturer) and he relayed how one property he visited had something like 100 PTZs connected to a single port (all terminated) and the system still worked. That would be an impedance of 1 ohm (100/100) at the transmitter.

[Bluzman23 0]

Thanks Carl.

I am an electrician by trade so when looking at a diagram in the manual to one of my DVR it looks as if the data cable is run in Parallel.

I can provide a unique address at each cam and match it on my dvr, so if I ran homerun cables back to the dvr/ controller and then paralleled them with a pig tail splice and put 1 set under the 485 control wires, would this work?

If i am correct when using the dvr/ joystick Lets say I wanted to activate cam 1 it would send a signal out on all my wires since they are paralled but only the cam with address 1 would activate.

This would also make each cam the end of line, so then would I turn on the termanition ponit of each cam?

Just trying to figure out the basics.

 

In the manual from the DVR Everfocus Ecor8D is the model I have it shows paralleling 3 cams from the dvr in a dasiy chain setup with the termination resistor on in the last unit only, which reflects what you said earlier.

[Soundy 1]

Whether you homerun all the lines, or daisy-chain them, the cameras are all still in parallel. I've only even home-run them all, and never found that it made a noticeable difference whether the cameras were terminated or not, but if you're daisy-chaining, you probably want to set the termination properly (last camera only).

 

Personally, I don't see the point of daisy-chaining - you're home-running all the video runs anyway, and usually the power runs as well, so to loop the signal line from camera to camera seems unnecessarily complicated... unless you use two-pair-or-more wire to the cameras and "daisy chain" the runs near the DVR (ie. one pair to the camera, other pair back, tied to the pair going to another camera, etc. etc... like I say, unnecessarily complicated).

[survtech 0]

Soundy: home-running multiple PTZs to the same port is, in many respects, the same as daisy chaining. If all PTZs attach to the same port and all are terminated, the net impedance would be the same as if they were daisy-chained and all were terminated. So 2 PTZs would net 50 ohms; 3 would net 33 ohms, etc.

 

Home-running multiple PTZs and tieing the data cables together could potentially cause signal reflections and intermittent control issues. It's not too likely if the terminations are proper and remain in place but if a termination is removed from one or more lines, it becomes more possible.

[Bluzman23 0]

Thanks Guys. As the weather breaks I will start to run out my cables to my ptz locations.

Matt you had replied to another post I had about a ptz controller suggesting a pc software based serial port idea. I have to look into this, would I then link the pc to my dvr via the serial rs232 port to operate the ptz funtions of the cams?

 

I am alwyas searching around mostly on Ebay for a ptz joystick controller, but mayeb I wll try the trial version of the software and see if it meets my needs.

 

Thanks again for all your Help Guys

[Soundy 1]

Thanks Guys. As the weather breaks I will start to run out my cables to my ptz locations.

Matt you had replied to another post I had about a ptz controller suggesting a pc software based serial port idea. I have to look into this, would I then link the pc to my dvr via the serial rs232 port to operate the ptz funtions of the cams?

 

Hmmm, no... you could connect the cameras' control inputs directly to the serial port on your PC and use the software to control them; you wouldn't interface the PC to the DVR this way.

 

RS232 is generally compatible with RS485 - although the latter is more tolerant of noise and supports MUCH longer runs, the former will usually work fine for smaller setups.