Outputs and Stopped Charts

So, if a chart turns on an output, will the output turn off if that chart is stopped or suspended? If the output has a watchdog, does the watchdog kick in if a chart is not continuously setting an output?


If nothing else is writing to that IO Unit, then yes. This is one of those features I never use, but probably should look into…

Clarification - Looking at the OptoMMP documentation and after testing this, the watchdog applies at the I/O unit level - so if no points are written to on the entire I/O unit, then the watchdog values get applied to the points that have the watchdog feature enabled.

So the answer is still yes, but you don’t need to keep setting the output that has the watchdog enabled, just maintain some form of communication with the I/O unit (packets passing over port 2001). So if another chart is communicating with I/O, the watchdogs will not be triggered.

Maybe someone can confirm this. I believe it’s true…

If PAC Display is requesting information from the I/O unit directly, it will prevent the watchdog from activating. So, if the processor stops but PAC Display is still requesting info, then you won’t get the watchdog feature to activate.

So, is it the setting/re-setting of the output or just communication to the I/O unit that maintains the watchdog?

For questions like this, I always RTFM… Read The Fantastic Manual…

Page 30 of Doc #1465, OptoMMP Protocol Guide. (http://www.opto22.com/documents/1465_OptoMMP_Protocol_Guide.pdf)
I will quote it here…

“(digital and analog points)—A watchdog monitors communication on the OptoMMP port (port 2001, unless you have changed it). If nothing accesses the port for the length of time set in the watchdog, the I/O unit automatically sets designated digital and analog I/O points to the values you have determined.”

To me, that is pretty cut and dry. ANY communications on port 2001 will reset the watchdog timer. It does not matter if it PAC Display, PAC Control or a .NET program. If there is activity on port 2001 it will reset the watchdog timer.

The SNAP-PAC or SNAP-Brain does not know [I]what [/I]is talking to it on that port, there are no special ‘signatures’ that identify the source of traffic on that port, it just knows if it is hearing traffic, don’t fire the watchdog.

Just a personal note, I really like that Doc 1465 and have read it end to end several times over the years. It’s a great way to get to know your Opto.

I like Read the Fun Manual myself…

Yes, Doc 1465 is pretty much the Opto22 bible to figuring how it all really works for me.

It helps if I keep my Fun Manual up to date. Version from July 2005 has the following…

(digital and analog points)—A watchdog monitors communication with the PC
or other host device. If the host does not write data to the brain for the length of
time set in the watchdog, the I/O unit automatically sets designated digital and
analog I/O points to the values you have determined.

You can see where the text has been improved on this subject. I’ll be sure to update my local files.

Ah yes, 2005… that might explain that…
No worries at all, glad we got your question answered.
The Fun Manual… Never heard that one… like it!

BTW, when I was in working at the hospital, as soon as Opto put the ‘My Opto’ subscription page into action I jumped all over it.
I signed up for everything. Now, as soon as a new version of a manual or product comes out, I get an email with a link. Too. Easy.
It was the only way that I could keep up-to-date.