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Messages - congo

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1
Technical support / Re:Method for causing events at counter PV intervals
« on: April 18, 2018, 02:29:32 PM »
Thanks Gary, once again you are right. I like the limit implementation because it keeps it simple and so far test runs show that it will work well.

Other methods of reloading to the HSCPV[n] work, but risk missing counts and skewing the real counter PV. Thanks for your quick and detailed suggestions.

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Technical support / Re:Method for causing events at counter PV intervals
« on: April 17, 2018, 06:00:58 PM »
Thanks Gary,

pulses are coming in on this high speed counter at about 50Hz so I'm thinking the delay of when the HSCPV[n] interrupt allows the cusF to execute might be a problem. I can't afford to lose pulses in the time that HSCPV[n] is reloaded also. The total accumulated pulses at the end of any given accumulation must be the same whether I'm reloading the counter for this interrupt purpose or not. This might be a problem in this application, not sure.

I'm also not quite following:

 HSCPV[1] = HSCPV[1] - 100      ' Reload counter with residual count value

Won't this cause HSCPV[1] to decrement constantly? In this case the HSCPV[n] always counts up due to the single direction of the sensor wheel.

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Technical support / Method for causing events at counter PV intervals
« on: April 17, 2018, 02:44:12 PM »
I'm looking for a method to trigger a math equation at intervals of a HSCPV[n] as it accumulates.

For instance, as the counter accumulates 100 counts, solve the math equation, then after another 100 counts solve it again, continue to do this after each 100 counts until the HSCPV[n] is reset from a separate part of the program. The counter does not stop at any point so the equation trigger needs to happen 'on the fly'.

One method I thought might work would be to use an IF statement. IF HSCPV[n]/100=1 THEN (equation here) ENDIF. The 1 could be incremented at each TRUE occurrence of the if statement. But even if the custom function rung clock is set fast at 0.01s it still seems to miss the IF instruction.

I'm sure there's a better way...

4
Technical support / PID negative saturation
« on: March 30, 2018, 01:11:21 PM »
When setting lmt in 'PIDdef ch,lmt, P,I,D' statement how is the negative part of the controller output usually handled? If the computed result drives the controller output all the way to its max negative value (i.e -100) there is an undesirable time delay for the controller to get back from -100 to 0 and then respond in the positive portion of its output.

In my example the PIDcompute(1,n), n is a scaled 0-100% value which is then further scaled to 0-4096 intended for a DAC output. When the controller cuts back the output it inevitably passes zero and hits -100 where my problem exists. I've tried scaling (Input-(-100)/200 so that the controller output scales the total lmt span of 200 from -100 to +100. Not sure if this is an effective way to handle this though?

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Technical support / Re:DAC stability
« on: March 30, 2018, 12:50:51 PM »
Thanks for the detailed response Gary, I'm working through your ideas.

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Technical support / DAC stability
« on: March 26, 2018, 01:48:38 PM »
When a DAC output is set to a value, and not moving when viewed by online monitor, why would the output voltage level move around? The output is connected to a 0-10V motorised valve actuator input and a signal fluctuation of about +/- 0.02V is seen constantly. The 0.2% movement is enough to hear the valve actuator hunting constantly. Is there a way to reduce this effect?

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Technical support / Re:PWM output
« on: February 18, 2017, 07:53:04 PM »
The SSR is DC on the control and load side, so yes. The combination of 'On and Off' time capability limits the output carrier frequency to less than 1KHz, which when operating below 1KHz creates too much heat in the 3.5Amp motor I'm using, so I need to find a solution where I can run much higher frequency.

If there is more literature available detailing the MOSFET/opto-coupler circuit included in the manual I'd like to give that more testing. I tested that on the bench (only had IFR520 so used that) but I couldn't seem to see the PWM SIGNAL on the output side of the optocoupler and as soon as the IFR520 was connected it seemed to stay 'closed' and the motor just ran. I eliminated the optocoupler (downside is the motor circuit is 12VDC) but found the MOSFET output acted inversely to the Nano-10 PWM output. When the duty cycle increased the output through the IFR520 slowed the motor speed.

Either I'll need to figure out what's wrong with the breadboard level circuit or source an amplifier board that can take the PWM signal directly from the Nano-10 and drive the motor. Help with either of these would be appreciated.

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Technical support / PWM output
« on: February 14, 2017, 01:16:38 PM »
An older post referred to using the IRF530 mosfet as a means to increase the amperage when switching larger loads, the response was to use an SSR. My expierience with this is that most puck style SSR I've tested are too slow and created excessive heat in the motor and poor control. Does anyone have any hardware suggestions for using the NANO PWM output to drive a 12VDC motor up to 7 amps?  

9
Technical support / CANBUS
« on: May 21, 2016, 05:57:57 AM »
Are the FX series CANBUS capable now? If so, where is the supporting documentation found for programming and using the protocol with the PLCs?

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Technical support / Re:Save value from slave during power loss
« on: April 29, 2016, 08:53:35 PM »
That worked well thanks. I also am testing to implement your suggestion for restoring the good count value in the slave, but having difficulty figuring how to write to the same DM[] as the slave HSC is.

In the slave PLC DM[1] =HSCPV[1], and the master is reading the same DM[1] for the count value. When I send a restored count from the master, DM[1] just gets overwritten by HSCPV[1] in the slave.

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Technical support / Save value from slave during power loss
« on: April 29, 2016, 10:44:10 AM »
If a slave PLC is being read by the master (via MB) and the slave loses power without backup memory installed, does anyone have a suggestion for saving the last good DM[] value in the master PLC?

For instance if a counter value (in slave PLC) is being read by the master into DM[] when the slave suddenly loses power the current number of counts is lost. Could a line of code be written to capture the counts continously but keep the last good value in this situation? Is there a code solution to this rather than installing extra memory in all the slaves?

Thanks.

12
Technical support / Re:Count pulses on pulse frequency inputs
« on: April 27, 2016, 04:32:41 PM »
So to trigger that:

Does the INTRDEF18,cfnum,x get initiated in an initial scan triggered custom function? Then calls the referenced custom function of choice on a ladder rung?  What contact if any is on that rung?

I'm not too sure how to construct that and haven't found a full explanation of it in the documentation yet.

13
Technical support / Re:Count pulses on pulse frequency inputs
« on: April 23, 2016, 07:02:10 PM »
That works thanks. Alternatively if the pulses are not that high of speed (10-30Hz) is there a way to count theses pulses while utilizing all 4 PULSEFREQUENCY[] inputs? I'd like to use 4 sensors wired to inputs on the FMD8810 for 4 separate conveyor speeds as well as accumulate pulses on each channel.

For counting purposes I've tried using a normally open contact driven by one of my prox sensors which energizes a {dCusF} containing a line of code like:
DM[6]= DM[6]+1. This works but misses pulses occasionally due to the program scan time, not adequate.

If all 4 PULSEFREQUENCY[] channels are fast enough to measure frequencies of 100Hz+ then I'm thinking I should be able to capture and count pulses without resorting to calling the HSC. Is there another way?

14
Technical support / Count pulses on pulse frequency inputs
« on: April 22, 2016, 12:14:31 PM »
Can someone tell me what the best way is to capture the accumulated number of pulses on a PULSEFREQUENCY[] channel.

I'm using the input channels to measure rotating frequency of a conveyor but would also like to capture the number of pulses on that same channel.

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Technical support / Web browser greyed out
« on: December 18, 2015, 12:12:30 PM »
I modified the .HTM file according to what I needed for interface to Fmd88-10 via iphone/ipad on a wireless network. All seems well except now when connecting with anything except iphone everything on the faceplate is completely background grey, no buttons or lcd etc. However connecting with iphone the interface is fully functioning and appears as expected. Not sure what the problem could be to allow normal browser  with an iphone but abnormal with ipad? Tried a few devices to rule out one particular device issue. Thanks.

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