PTZ controller will not control over 9 cameras - Pelco

[NHSS 0]

I have a situation where the person installing Pelco Spectra PTZ cameras wired both daisy chain and star configuration. Each of two controllers, pelco KBD300A with direct hookup will only work with up to 9 cameras.. They are using pelco-p 4800.

My hand held tester can control them.

Pelco stated I had to buy their port isolator - CM9760-CDU-T.

 

Does a different controller have to be RS-422?

Is there a better suited controller ?

Since they are Pelco do I need this port isolator

[survtech 0]

I'm not familiar with that keyboard. Is this an address limit issue (the keyboard can only access 9 addresses) or a termination issue?

 

If the keyboard can only handle 9 addresses, a CDU-T wouldn't help at all. If the problem is the load, there are two ways to solve it: one would be to use a CDU-T and "star" each PTZ to it (or for far less $$$, a Kalatel KTD-83) or just turn off the termination on every daisy-chained PTZ except for the last one.

 

Star PTZ control deployments to an unbuffered port are usually frowned upon. The issue is called SWR and what it means is that the control pulses echo around within the star and can cause lost or duplicated command signals. Star connections should be made using a "buffer" for each leg. That is the function of both the CDU-T and the KTD-83 (and other RS422/485 code distribution units.

 

By the way, the code distribution units (the "CDU" in CDU-T) can be placed in the field so that control wires don't have to be home-run to the controller. The KTD-83 is smaller than the CDU-T and easier to mount on a wall or above the ceiling.

[hardwired 0]

I have KBD300's controlling twelve cameras, it's not an addressing issue. Are you trying to use both keyboards at the same time? that may cause problems.

 

Try with only a single keyboard connected. In our installation, we used a CM9760DMR to merge two keyboard data outputs into a single output to a CDU-T.

 

If you have a matrix (CM6700/6800, or similar/higher), it will also merge the keyboard data lines.

 

If you can, please try to post a diagram showing the configuration and addressing settings, and which cams have termination on/off.