Wash / wipe instruction in pelco? protocol

[CCS 0]

I'm building a system for an image processed security system around a jetty. As the system is monitored by computers rather then people, I need to somehow occasionally issue a global camera wash / wipe to help the image quality in the case of sea spray etc.

 

My image processing vendor does not normally do this, but it should not be too hard to do something myself here.

 

I can either have a hardware system that fires a relay every so often for a short interval or I can write a program that issues the command every so often.

 

The second option is preferrable as I'd like my vedor to eventually incorportate this feature ( and suspend analysis triggers on the wiper motion ). It needs to be something that a data transciever (preferably common and cheap) can handle, therefore possibly pelco protocol.

 

I don't want to reinvent the wheel here. Has anyone done this before or can help in finding the command I need? I'll obviously share my piss-poor code with whatever I come up with if I need to do my own thing.

 

Cam

[jisaac 0]

man why dont yoiu just hook up a wiper to a motor and wire that back to the appropriate power supply and then hook it up to a relay and a timer like the appliance timers that will turn lights on and off during certain times and days. That would very simple.

[CCS 0]

The cameras are for a petrochemical plant and have approved hazardous area ratings that I cannot modify without a potentially large recertification effort.

 

Also, if I can do it in code then I can take into account the wiper in the image analsis so unnecessary alerts are not triggered.

 

Thirdly many of my cameras are over water and inaccessable. It would be nice to be able vary the wiping rate depending on the weather so to mininmise the need to refil the reserviors. It would be nice to do this without leaving the nice warm control room.

 

Cam

[Billyk 0]

Don't know if this helps... Have you looked into PIC? If you Google it there are many automation resources involving PIC compatable controllers, etc.

[KrCCTV 0]

Programmable Logic Controllers (PLC's) will give you all the control you need. Typically programmed in very easy to learn Ladder Logic (or newer ones with funtion block programming). Scalable, with built in real-time clocks, timers, counters all pretty standard. Basically a small specialized programmable industrial computer, power supply, backplane and I/O Modules designed just for applicatiions like yours. Now often also monitored / supervisory controlled with graphical user interface software that runs on a PC. Need to count output points and consider using very low voltage relay outputs with intrinsically safe (IS) barriers to the wipers (typical in hazardous environments - can't cause sparks). The "controls" folks at the plant will likely know all about PLC's and/or maybe in their case DCS Systems (Distributed Control Systems) and may be able to direct you to an automation systems integrator who could very easily do the work if it's beyond something you want to get in to. Ideally somebody who already does work at the facility, etc. Additionally they are probably standardized on one manufacturers PLC or another and might be especially interested in having you use the same for lots of good reasons.