Dome Shutter Remote Issues

Monday, November 26, 2018 11:14 AM

Problem(s) Encountered:

Numerous issues were reported regarding failures with operating the dome shutter and dropleaf remotely.  Below is a rather lengthy discussion of the issue and it’s potential solution.


The system this morning was configured with the dome slit control connected to port 2 on a newly procured VLINX box.  This was done to mirror the configuration on the old box, which had a dead port 3.  Port 3 used to be used for the dome, but when it failed, we moved it to port 2.  So this morning, I shut down the TCS electronics and swapped slit control back to port 3.  When I brought things back online, the dome slit functions were unresponsive.  That got me wondering about TCP port assignments.  I checked TCP port assignments and decided to make some modifications so that the TCP port assigned to the physical port 3 was now the TCP port that was previously assigned to the physical port 2.  I know this is confusing, so see below for the changes:



Initial Configuration this Morning   Failed Modification this Morning   Successful Modified Configuration

Port    TCP Port                                    Port       TCP Port                                   Port         TCP Port

1              0                                               1                 0                                            1                  0

2*            1                                               2                 1                                            2                  2

3              2                                               3*               2                                            3*                1

4              3                                               4                 3                                            4                   3


*Port connected to slit functions (rslit)


So I went back into the configuration software (which I have on the administrative account for the 1.3m guider PC) and swapped TCP ports between physical ports 2 & 3.  This is reflected in the last config shown above.  And interestingly, remote dome control seems to once again work.  Monitoring both ports 3 (connected to rslit) and port 2 (unconnected), I no longer get odd connections to that fail to disconnect.  In fact, I don’t get connections at all.  That said, once, and only once, I did get a connection to .115, interestingly, on port 4, which required me cycling the servers (telescope stop/start) to get things back online.  That said, numerous tests were performed and the system only hung once, and again this time, associated oddly with port 4.


For tonight, I plan to leave the system ready for full remote use and see if there are any problems for the team running it remotely (from S. Korea).  We’ll see what happens.  In the meantime, I’m hoping that this new information not only leads to a more stable system, but possibly also a revelation on what was going on over the past few weeks.  

Lastly, it’s worth mentioning that previously, port 2 was used for communication to the weather station, which has not been a part of the system since before I started at MDM, now over 6 years ago.


Took a look at the 13m.h file where the port assignments for the VLINX ESR904 unit are made for the TCS programs:


    Port 1 (mdm13ps3,4000): PMAC

    Port 2 (mdm13ps3,4001): WEATHER

    Port 3 (mdm13ps3,4002): SLIT

    Port 4 (mdm13ps3,4003): ADAM (Advantech ADAM-40xx analog I/O pucks)


Port 4 is invoked from the slit.C program (methods Slit::Taux(), ::SlitState(), and :: slitCommand()), and from digits.C and observatory.C.


Not sure if this gives Dick Treffers ideas as to what might be going on. [Pogge]