Serial Servers?
vining
Posts: 4,368
I'm currently bidding a project where I will need to control 5 serial devices in the master bedroom and my current inclination is to use a 8 port serial server from Digi or Lantronix or Moxa. I've never used a multiple port server but I assume for comms w/ the master all connected devices will use the same IP address and what ever virtual port number I assign the server for which ever physical port I choose. That should be pretty straight forward but if I my assumptions are wrong let me know. My real question is IR for cable boxes or what ever, my thinking is I should be able to send IR this method as well. Has anyone done this before? Can I just connect a flasher to GRD and TR? Would I just use a send_string with the complete HEX code for each command?
I can get an 8 port serial server for under $800.00 and 16 port for under $1,000.00 retail which is far less expensive than the alternatives. I'm also thinking above using these to expand serial ports at the rack as well when I need more serial ports than the master can provide.
Any thoughts?
I can get an 8 port serial server for under $800.00 and 16 port for under $1,000.00 retail which is far less expensive than the alternatives. I'm also thinking above using these to expand serial ports at the rack as well when I need more serial ports than the master can provide.
Any thoughts?
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your chances of getting the IR to work over the Digi expander are very slim. it's vaguely possible, but would take a lot of development, and then it still may not work for various technical reasons.
i've used the Digi for getting serial commands over a LOCAL network to a serial device, FROM A PC RUNNING WINDOWS. the thing is, Digi supply a driver for windows that fakes a serial port in the operating system, then finds a remote Digi device and passes the commands to it. so this setup may not work for Netlinx, as the driver protocol isn't documented (that i've found).
you would need to find a network to serial device that lets you use an IPnumber:Port to Serial:Port control. i.e. 192.168.0.100:8081 to serial port one, 192.168.0.100:8082 to serial port two etc.
if you can do that, then netlinx just needs to send a string to IP:Port, not caring what's on the other end. you will need to modify all code to readdress the required Netlinx comm ports to the remote IP:Port.
in basic terms, another master controller is the simplest and most convenient way to achieve this using master to master links. it doesn't require a lot a program changes to achieve.
i know it may be a bit more expensive hardware wise, but you'll probably save time and money and support just using another master. you'll also get the IR emitters in a convenient location.
i hope that helps.
I already use the DIGI TS1 (I think) single server as a IP to RS232 adapter through Netlinx and it works fine. The DIGI actually has way to much capabiltiy for set up options and your right finding the right set up isn't easy. Most of these servers can be configured as a straight TCP or UDP to serial adapter and you can set the virtual port to what ever you want with out using the virtual comm port application or port replicator. I would think the functionality of the 8 port server would be the same as having eight single servers the only difference being with the 8 port I use one IP address and 8 virtual port numbers and if I use 8 single servers I would need to use eight different IP addresses but my port numbers could all be the same.
The IR to me sound like it could work but I just don't know if the voltage is enough to drive the Flasher but my guts thinks it might. I have a DIGI TS1 in stock and if I had the time to spare I'd give it a try but right now I have to get this price together and don't have a day to waiste.
And your right, I could just play is safe and spec an NI 3100 and be done with it and if I supply it cost it's only a few hundred more and even if I mark it up it won't be so bad in the scope of this project.
I'd still like to know if IR is possible w/o having to try it myself.
i'll take a look at the TS1 (to see if they are different or if we are talking about the same thing)
i'd be very curious if someone had some code to flash ir over a serial port. i have seen some, but it was at low level hardware control, to enable certain lines hi/lo and for timing.
the technique was a bit cpu intensive as it required some fast (and fudged) control of the port (i looked at this for a PC serial port IR flasher in C++).
basically, it used RTS or CTS enabled to provide the carrier voltage to the transmit LED, then used TR or another line to do the pulsing.
also, you need to capture the IR with the same technique and it's only a 'snapshot' of the IR, not a structured IR data capture. you would then 'playback' the binary file in it's raw format/recording speed. the problem with this is that existing IR libraries may not work and you need to record all required IR codes again.
it would seem i had things wrong on the usage of the Digi, so i wont go out on a limb again too far... but i think trying to do IR over the remote serial port would be tough. huge kudos to you if you get it to work.
http://globalcache.com/
Though I'd say you're probably better off with another processor. It's a lot easier to maintain, you can offload your device driver code to it, you can use the same format IR files throughout the project.
This looks like it has possibilties and for $299.00 / $368.00 it is very reasonable. Extron has some stuff like this too but are likely more expensive. It would be just what the doctor ordered if it had more serial ports.
GC-100-12 or GC-100-18 (18" w/ rack ears)
? Power input ? 12 to 18V DC@500mA (wall power adapter included).
? Network connection ? RJ45, 10Mbps.
? Two serial ports ? Male DB9, RS232 up to 19.2Kbaud bi-directional with hardware flow control.
? Three relays ? Screw terminal plug, 24V AC/DC@.5A N.O. contact with transient voltage suppression.
? Six independent user selectable IR outputs or sensor inputs ? 3.5mm mono jack.