Internet PLC Forum

If I call NETCMD$ on the same port from multiple locations in my program, will this cause problems?  Does one NETCMD$ call block others from accessing the port and force them to wait until the first one receives a response or times out?

I'm guessing it's because you're posting with the default account "Guest".   You have to have an account before you can modify your profile.

What timing!  I came here to ask this very question.   I've never even looked in the Omron section of the manual.

I still have one question, though.  Can these be mixed with native host commands?  The wording the manual makes it seem like you can but I just wanted to be sure before I implement these.

Not having used it yet but doesn't SETSPEED configure acceleration for you?  By experimenting, you should be able to arrive at a reliable acceleration for your setup.

I don't have a problem with acceleration -- it deceleration.  Specifically when interrupting a jog.

I've done some initial experimenting with Dan's suggestion and so far it seems promising.  In the custom function where I normally STEPSTOP the motor when jogging I now check to see if my speed exceeds some threshold.  If so I proceed to issue STEPSPEED's that cut the speed down by 10% every 20ms until I'm below the threshold at which point I issue a STEPSTOP.

Initial tests have been encouraging.  At speeds above some configurable threshold I can come smoothly to a stop with a little overtravel.  Below the threshold I am still able to stop on a dime by issuing an immediate STEPSTOP.

I've implemented a jog feature in our 888 program by sending large values to STEPMOVE and issuing a STEPSTOP when the jogging is done.  However we recently uncovered a problem with this technique that somehow escaped our notice before.  If the speeds are too high suddenly stopping the motor with STEPSTOP results in the motor skipping a number of steps (due to momentum) which knocks the position off.

One solution is to limit jog speeds but this is very unsatisfactory since the speeds would be too slow to be useful in our application.

So consider this post an enhancement request for future versions of the Triplc firmware.  I'd like to either see some jog functions added (maybe even simplifying the use of an analog input for speed control) or at the least add a deceleration parameter to the STEPSTOP command where obviously a decel of "0" would make it work as it does now.

I was surprised to find out that I can't run a second instance of TLServer so I can connect to two PLCs simultaneously.  What is the reason for preventing this?  If it's a TCP port issue couldn't it just take the next available port (9081)?

It won't matter in my application as I don't use TLServer normally but during development it's handy.

I've only started looking into I2C this past weekend so I'm not even sure if this question makes sense but is there a simple way to interface with I2C devices using the 888 PLC?

I've seen adapters for communicating with I2C devices using RS232, USB, and parallel ports and some seem pretty simple.  Isn't there a way to use the I/O on an 888 to do the same?

And if there isn't, maybe that's something your PLCs could offer in the future?  An I2C header somewhere on the board?

The n parameter of the setPWM function represents the channel number, not the output number.  It should be set to 1 or 2, which correspond to outputs 7 and 8 respectively.  It documentation is a little confusing on this matter (mentioning that n should be a number between 1 and .

I don't understand what you were saying in the second half of your post but you shouldn't be doing anything with output 7 elsewhere in the ladder if you intend on using it as a PWM output.