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RS232 Comm problem - Very strange
ipssheldon
Posts: 106
in AMX Hardware
I thought that I would document a strange problem that I experienced at a jobsite this week that doesn't make any sense. If anyone else has seen this or has a plausible explanation, I'd be curious to hear them. As you will see, we were able to resolve the issues, but this was a strange one. Here is the scenario:
4 rooms. All virtually identical.
Each system used an NI-2100.
Com1 was a document camera (either an Elmo or Wolfvision).
Com2 was a Panasonic PT-F200NTU projector
Com3 was an Extron MLS406 Switcher
The first room worked fine. Absolutely no issues.
In the second room, we had all kinds of trouble trying to communicate with the Panasonic projector. We verified that Com2 on the NI-2100 was working fine and that the comm port on the projector was working fine. Protocols, baud rate, etc. all verified as correct (and same as Room 1). We finally decided to swap ports 2 and 3 (projector and switcher) and we found that the projector control started working. We swapped back and found that everything worked great.
We went to the third room and found the very same problem. Again, we went through the process of verifying the hardware and only after we swapped the projector and switcher, could we get the NI-2100 to control the projector.
In the fourth room, when we again ran into the same problem, the only thing we did was to swap the switcher and projector between ports 2 and 3 and the projector would work on either port 2 or 3. But the projectors, in each room, other than the first room, would not work on port 2 until after we swapped it with the switcher.
The cables were the same in all cases (pins 2, 3, and 5 only). What could possibly have been the issue that required either the projector to connect to port 3 first or that required the switcher to be connected to port 2 first.
The good news is that we were able to fix this issue in each room, but I am at a loss as to what would have caused this.
Just curious if anyone has any thoughts.
Sheldon Samuels
4 rooms. All virtually identical.
Each system used an NI-2100.
Com1 was a document camera (either an Elmo or Wolfvision).
Com2 was a Panasonic PT-F200NTU projector
Com3 was an Extron MLS406 Switcher
The first room worked fine. Absolutely no issues.
In the second room, we had all kinds of trouble trying to communicate with the Panasonic projector. We verified that Com2 on the NI-2100 was working fine and that the comm port on the projector was working fine. Protocols, baud rate, etc. all verified as correct (and same as Room 1). We finally decided to swap ports 2 and 3 (projector and switcher) and we found that the projector control started working. We swapped back and found that everything worked great.
We went to the third room and found the very same problem. Again, we went through the process of verifying the hardware and only after we swapped the projector and switcher, could we get the NI-2100 to control the projector.
In the fourth room, when we again ran into the same problem, the only thing we did was to swap the switcher and projector between ports 2 and 3 and the projector would work on either port 2 or 3. But the projectors, in each room, other than the first room, would not work on port 2 until after we swapped it with the switcher.
The cables were the same in all cases (pins 2, 3, and 5 only). What could possibly have been the issue that required either the projector to connect to port 3 first or that required the switcher to be connected to port 2 first.
The good news is that we were able to fix this issue in each room, but I am at a loss as to what would have caused this.
Just curious if anyone has any thoughts.
Sheldon Samuels
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Hello Samuel!
Please write configuration commands which you send to port 2 and 3. Maybe configuration command which you send to port 3 have different setup information with command which you send to port 2. And command from port 3 necessary for normal projector works.
SEND_COMMAND dvProj,"'SET BAUD 9600,N,8,1 485 DISABLE'"
SEND_COMMAND dvProj,"'HSOFF'"
In what part of the program are you sending these commands?
DATA_EVENT[dvProj] { online: { wait 20 { send_command..... } } }These are all great ideas and all are the same things that we thought of and tried.
Like I said, it wasn't until we connected to port 3 that the controls started working. The only difference being the physical difference between ports 2 and 3 on the NI-2100 that I can determine.
Actually, now that I think about it, the only possible additional change, might be something buried in a Duet master and the dynamic device discovery process. If the NI-2100 detected the Extron switcher and auto-configured the port differently, than the program was configuring it and if this occurred initially on port 3 and then on port 2 when we swapped the cables, then I guess this could be what got things working. But the program was not using any duet modules at all. The site does use Meeting Manager so the associated modules for Meeting Mgr were included.
Anyone come across this before?
Strange. Very strange.
Sheldon Samuels
This may have caused an issue if as you say Discovery was operational...
It is also a good idea to be totally specific with port config commands - just in case something gets moved around or another master is swapped in with a previous config.
You may have just got unlucky with 2 NI2100 that had been loaded previously. Alternatively did you reboot the master more than once prior to changing ports 2 & 3?