Internet PLC Forum

I have a similar problem as Monty K below whereby I also have a master & 9 slave T100MD's all connected together via their RS485 ports, though in my case each of them are connected to an ethernet network via individual nPort express RS485 to ethernet converter server units.
The problem I have is that the system will function happily for over a day without incident and then for no apparent reason all the slaves will lock up!
I've incorporated a MaRST facility into each slave where if I press two buttons simultaneously the PLC will reset (which normally works OK),  but when I get these lockup conditions occuring the MaRST doesn't work. Only a complete power down/power up cycle works, which is far from  ???ideal!
Do you have any idea as to what maybe causing these simultaneous lockups occuring, and why the MaRST facility doesn't work when it happens? ?

Thanks for those very useful examples. All is now made clear (except you got the Hex value equivalents the wrong way round.

As for the Wb command, this unfortunately wasn't contained in the blue User Guide manual that I received with my T100's, so thanks also for refering me to the updated version on your site, which I've swiftly printed out!!

Thanks for that!  It's so easy when you know how!

I've used the routine both with and without REFRESH but I still lost counts.
I have since utilized another T100MD as a slave unit and have six counters incorporated in a small routine. Tests using the conventional I/O input to each of them now seems to confirm that all counts are now being recognised. The interupt method i.e. INTRDEF 1,4,1 where Cusf #4 contained CtrPV[1]=CtrPV[1]+1, so as to increment the counts, didn't appear to work, as counts were still being lost.

I have in fact 3 outputs to change rapidly so will your suggestion of " try using the SETPWM command to drive the PWM1 and PWM2 outputs to 100% (ON) or 0% (OFF) " still work?

I'm running a program of around 6.5Kb on my T100MD which takes in a rapid pulse train and operates a number of outputs also in a rapid fashion.
Unfortunately counts are being missed due to the relatively long scan time for this program (using the HSC is not an option as this just triggers CusF's and my requirement is too rapid for these to execute in the time available), so I was wondering if sharing the program between a Master T100MD and a Slave T100MD would be an option.
I would use the Master to run the main control program, while the slave would service the high speed counting of the pulse train, and the high speed operation of the outputs.
I have three questions:
1) Can I simply connect them together via the digital connectors (as you would do with a 4040 board), and have direct access to both eeproms, so that I can upload 1 program of say 5kb's into the Master and one of 1.5kbs into the Slave, thuse reducing the scan time on both? Or will I need to connect them together using the RS485 method?
2) Would this arrangement allow me to easily control the Slave from the Master, and to pass data to and from each of them?
3) Would this arrangement be more straightforward to do, rather than using an E10 as the slave (can this acquire a high speed pulse train too?).

I have a situation where I need to have the PLC to accurately count a pulse train at a max frequency of around 100hz but more typically at around 70hz (~14ms/cycle), and acting upon a each cycle to perform an operation when required.  Normally this wouldn't be too much of a problem for a very small program (I've tried it and it works) BUT the size of my program is around 6.3 Kb (near max capacity), so the PLC's scan time now becomes a problem insofar as pulses are being missed.
Using the HSC appears not to be an option as although this function can easily count at much higher speeds, it's the amount of time it takes for the HSCDEF function to perform it Cusf operation that again causes timing problems.
The only way I can think of overcoming this problem is to have a faster scan speed, so would overclocking be an option to explore? If not, do you have any other ideas? Thanks.
PS Are you planning to release a faster PLC soon with larger memory?

The ADC ports apparently divide a 5v level into 1024 bits, and then this is multiplied by 4 (to 4096) for some reason, which is why I think you are getting your +/- 4 variation.

Could you please tell me what the typical scan time is for a program of approx 6000 words (max capacity of PLC), and would it be half that time for a program of 3000 words i.e. is scan time directly proportional to program length?