Way to test RS485 Port from DVR either PTZ cam

[washingtonianCCTV 0]

This is my knowhow but if you have more than this, please post it

 

1. measure DVR RS485 port while sending signal (zoom +-, focus) make sure, you get more than +-1.5V difference compared to normal voltage (w/o sending signal from DVR), if voltage difference is more than +-1.5V, DVR should be OK.

 

2. same thing to PTZ, but PTZ voltage difference is +-200mV (DVR +-1.5V) in other words, while sending signal from DVR to PTZ, if you measure PTZ side, you may read voltage difference.

 

3. Use Oscilloscope to measure voltage difference (voltage meter is not accurate to detect sensitive difference sometimes)

 

4. Buy RS485 Tester, which i don't like it because it is only measuring voltage difference.

 

5. Buy RS485 test utility, which I like to do, but very expensive, but you can get all information, real data, speed, baud rate etc.

 

6. Ask manufacturer for testing jig

 

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[bpzle 0]

Use an rs484/485 to rs232 adapter and use some sort of COM tool on a computer that understands HEX codes.

 

Compare this to known protocols.

[zmxtech 0]

Another way is to loop the remote end to test it end-to-end

[Soundy 1]

Use an rs484/485 to rs232 adapter and use some sort of COM tool on a computer that understands HEX codes.

 

Compare this to known protocols.

www.serialporttool.com has a good selection of protocol analyzers and utilities.

[johnnyviper 0]

Well it sounds like your more interested in the actual logic of RS485. Here's a really cool tool that I came across a while ago. One of these day's I'm going to have to order one to try. For $149 I don't think you could find a better logic analyzer!

 

http://www.saleae.com/logic/