Reply With Quoteguess no one knows,or am i in the wrong place?
questions about rs485
hi i have a few questions about rs485 main is:
can i have 2 rs485 adapters on 2 seperate pc machines so i can config the cam with 1 pc and control the camera with the cctv server via the adapter on there,
so like pc1 cctv server, rs485====>cctv camera<======pc2 rs485,config pc
or will they conflict?
other questions,what else can rs485 be used for? can i make relay boards same/similar to the serial/paralel port ones? ,like send a command thru the cable, and turn on/or off a relay
the nice distance rs485 goes,could be handy for use of a relay board remotley switching power on and off
thanks
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guess no one knows,or am i in the wrong place?
Yes as long as they are sending at different times it can be done.Originally Posted by badboyheathy
Many camera's, PTZ controllers, alarm systems have relays that can be controlled by the rs485 input.
thanks, just baught another converter,
now, lets see if i can find some rs485 relays,that i can control,,if i can even find any,if i do, lets see if i can control them( i wish to be able to control relays,as switches,turning 12v ledlights on and off,using,well hopefully the same data cable as the cctv, if nothing else is using it, it shood work,,just have to find some CHEAP ones if any
thanx
Im no expert on 485 but this may help, it is how I understand it. Please correct me if I make any mistakes.
there are all sorts of devices that operate on rs485, however rs485 is just a comms protocol not a fixed command set or anything like that.
PTZ camera controllers use rs485 to send pre-determined code "words" or blocks that the camera decodes the code and uses it to, for example zoom in.
Other systems such as security systems use rs485 to communicate between different modules that may consist of all sorts of interface devices such inputs, relays, card reader heads and so on, you can work out some of the "code" for some devices but others use encryption.
Rs485 is just one of many comms protocols; similar ones include rs232 or rs422. It can also be half duplex or full duplex (google this) You should also be aware that you chosen protocol can also work at different speeds, better known as baud rates and devices to be controlled must have the same baud rate.
There may be open source devices out there that use rs485 that you can control from a serial port or similar but this may not be the place to get good answers. There are security devices out there that control relays, cameras and more that should meet your needs but at a price.
Also a standard PC serial port will pump out rs232 not 485, you will require a convertor as mentioned.
thanks for thatyea, everything rs485 is at a price..
as u said baud rate and encryption,coded,yea dont sound as easy as i want
if there was some kind of DIY kit to control minimum 5 relays(to switch on some 12v LED lights),reason being rs485,is i have ptz cameras already there,and if i could use the same comms cable, as the cameras,and the distance rs485 can go,there may be a kit out there for what i say, or a adressable rs485 to rs232 converter,to make it back to rs232? and then find(if there even is) a rs232 relay controller,
thanks all
you can get ptz cams with relays and possibly inputs controlable over 485/422 via a ptz control board or pc/dvr.
quite handy when u have a ptz on a gate or similar then you can open the gate from the aux output.
good thaught, those control boards, i wonder if more than 1 relay can be clicked on at once, i have a bit of software where i can send commands to the unit,where it needs 1 to close circuit, and 1 to open, im have to try and see if it does, if it does, il have to mod the board, because out each relay,comes 24vAC,so, i euther get, 9 24 to 12v converters,..... or mod the board cut the 24v supply off and mod it for 12v in,or, find several 24v AC relays,do they exist? i no dc do, but ac relays? all the 12v i have say on side 12vDC
sure do, in all sorts of AC voltages and currents and so forth. And electrical supplier or any good electronics shop (NOT Dick Smith) should have some. If I understand correctly your relay contacts close and give you 24v from somewhere, so just use the 24AC to fire your separate relays.
firing two relays at the exact same time over 485 is tricky as the communications are serial so in theory your signal to fire the second relay will follow a uS or so after the first. You can get around this by having one relay fire two "slave" relays. Or more technically your module may be able to use a single command to do more than one thing. Another option is a small delay on the first operation. Can be a real pain if you need very precise timing.
What “boards” and software are you using, all this talk about 485 has got me interested and I want to learn more!
Call Pacific Communications, they have a great box that allows for 2 RS422/485 inputs to go to one output. Talk to the Boss's there, mention that it used to be used on the 9700's and 2350's Matrix Switches...
ReD
dick smith is useless! lol
i would us them to fire seperate relays, but what i exactly want is to keep it fired, until another command is sent to fire again and release, as in, is a press on press off switch was under a relay, wen the relay "clicked, then released" it pressed the on/off button making it on, click and release again wil make it off.
the board im useing, as actualy used for a PTZ head and lens, has 9 relays,so its strictlky designned for ptz use.
the bit of software im using is free version of CommFront 232 analyzer
with the downloaded configs of the pelco-d and pelco-p,
the software has the commands (up down left right,zoom focus and aux) with the supplied commands, only 1 relay can be fired on the up down left right relays the output has 5 wires,gnd and basicaly, relay1 2 3 and 4 the lens has 4, i think thats done by +/- changing, but 2 relays are being used,for zoom and 2 for focus,and last, is the aux, wichi think it is just a contact,
so, avoidong to "hack" the board, and make each one like a switch with a single command
What you need then is a trigger relay. pulse on, pulse to turn off.
Yes lens is +/- for direction, diodex2.....
can i make a trigger relay? i got loads of old relays sittin round doin nothing, so if i can make some, it wood be cheaper wouldnt it?
I use the
alfatron RS232-485 converters, which have a tristate output so you can connect multiple machines together with minimal risk of conflict.
It go open state if the CTS is not active
Tim Norton
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