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91
Technical support / Re: PLC Ignoring Timer
« Last post by garysdickinson on December 04, 2019, 03:33:15 PM »
There is something wrong with the PC6 file that you attached to the post.  When I download and try to open your file with
i-TRiLOGi 6.52 I get the following error message:
"Open File Error
Error Opening FIle C:\Users\ ...\1500.1.3.5-1.pc6
File Not Found or is is not valid TRiLOBI file"

I opened your file and the first line of the file is as follows:
TRiLOGI Ver 3.0<SUB><LF>

<SUB> has a value of 0x1a  and is named a substitute character<-- I don't know why this character is present
<LF> is an ASCII line feed character this makes sense

The first line of .PC6 files produced by the current version of i-TRiLOGI looks like this

øõTRiLOGI Ver 5.0<LF>

The first two characters are Unicode. I am a 7-bit ASCII guy..

Perhaps your version of i-TRiLOGI has some limitations on what sort of files it can produce.  Tech support at TRI will recognize the problem, easily.

If you can print out your ladder logic to a PDF and either post a link or send it to the email address in my profile, I'd be happy to figure out why stuff is not happening for you.

Best regard,

Gary Dickinson
92
Technical support / PLC Ignoring Timer
« Last post by MatrixMan on December 04, 2019, 12:05:39 PM »
We are a small manufacturer of EPS densifiers.  We recently added a High/Low switch to aid in densifying egg cartons which are very dense and require a different compression and grinding time.  To do this, I just added a relay with the switch input in high (see circuit #22).  Then for the compression time I copied the existing Circuit #24 and just added a new timer with a _H to show that it was the high mode timer.  It works fine.  Then I did the same exact thing for the grinder.  I copied Circuit #43 and created Circuit #44 with a new timer for the high setting.  The problem is that the Circuit #24 works fine, but Circuit #44 the timer stops and the grinder just keeps going.  They are exactly the same circuits so why doesn't it work?  It works in the simulator too.  The grinder just continues to run until the sequence advances and everything resets.  You can change the Grnd_Hi timer and it does absolutely nothing.  I would appreciate any feedback on this.  Thanks.

Here is a link to see what a densifier is: 

https://www.youtube.com/watch?v=eI0GMIiu9PI

You can see a man throwing foam into the grinder.  There are 3 compression chambers called pushes.  One push for each axis (x-y-z).  The program starts the grinder when the first push retracts.  Hope this helps.   
93
Technical support / Re: Custom Function Editing Window Issue
« Last post by support on December 03, 2019, 05:08:38 PM »
What is your iTRiLOGI version?

Try to upgrade to the latest version by following the "Help-> Upgrade TRiLOGI" link in your existing iTRiLOGI software and upgrade to version 6.6 or 7.2 which support 4K display on the 4K laptop that we tested.

If you already have the latest i-TRiLOGI and still having trouble with the Custom Function editor in 4K monitor, please post a screen shot of the custom function so that we can see what can be done.
94
Technical support / Custom Function Editing Window Issue
« Last post by DW_Microsys on December 01, 2019, 09:31:21 PM »
Issue: when editing function in the 4k monitor, the text in the window massed up. when using the laptop LCD, it works fine.
Laptop: MSI GL63, Window 10 pro, graphic card RTX 2060. 4k monitor: Samsung 55" smart TV connect with HDMI cable.

95
Technical support / Re: Programming to PLC
« Last post by plcdroid on October 15, 2019, 10:57:47 PM »
I also just learned about PLC.

But I have a reference to learn PLC easily
96
Technical support / Re: Changing STEPSPEED
« Last post by garysdickinson on October 14, 2019, 12:45:10 PM »
Hello Thierry,

In regards to issuing a StepSpeed command during an active step move command, what I have observed is:
  • The step rate jumps to the PPS specified by the new StepSpeed command
  • The "acc" argument is ignored. There is no ramp. The step output jumps to the PPS value in the new StepSpeed command.

My testing of the StepMove statement is that it is ignored while the stepper is executing a StepMove command.  This approach will not get the behavior that you want.

The PLC stepper motor control hardware/firmware is very simplistic.  It assumes that you just need to move a stepper from one position to another.  The acceleration/de-acceleration and maximum step rate is specified before the StepMove statement executes.

The only thing that you can do while a StepMove is executing is to abort it with a StepStop statement.  This command just shuts down the stepper control system and the steps are abruptly stopped.

I do use the StepStop statement in production PLC code. I use this to stop the stepper system when a switch is closed indicating that the system is in the "home" position. However, the move statement that I use to find the "home" position has the PPS set to a very low rate and no acceleration/de-acceleration is used.

If you are really in need of a variable speed stepper based system you have only a few choices:
  • Stick with the PLC. If you speed changes are great enough for your system to lose steps then you will need to issue several intermediate StepSpeed statements before you get to your next target speed.
  • Look into some sort of motion control system that is external to the PLC. For some motor control needs I use 3 phase motors and VFDs.  The PLC communicates to the VFD via RS-485 (Modbus RTU).  VFDs manage the acceleration profiles to smooth out abrupt speed change requests that the PLC may make.

Best regards,

Gary Dickinson
97
Technical support / Re: Changing STEPSPEED
« Last post by acxysty on October 14, 2019, 03:19:40 AM »
Hello Gary

Thank you for your answer.

I will think over you suggestion and make measurments.
I would have thought that setting a pwm to a new value would have produced a brutal change in frequency like it is the case on micro-controller.

That raises another question related to my first post : What happen when you apply a STEPSPEED command immediately followed by a STEPMOVE command while still in the middle of the previous STEPMOVE command ? According to some older posts the built-in stepper motor pulse generator will modify its parameters (frequency and number of pulse). How the frequency transition will occur ? Brutal or according to the acceleration law define by STEPSPEED ?

In advance thank you for your replies and you help !

Regards

Thierry






 
98
Technical support / Re: Changing STEPSPEED
« Last post by garysdickinson on October 13, 2019, 04:23:30 PM »
Thierry,

You will have to test this.  I have tested most of the stepper motor hardware and firmware, but have not attempted to change the PPS (step rate) of a running stepper. 

I do use the PWM outputs to generate variable frequency pulses.  The PWM outputs will change frequency while running. I have verified this with a digital oscilloscope and see that the output goes to the new frequency very "cleanly".  You could use a PWM OUPTUT to control a stepper motor and change the frequency, periodically.

The following code has been extracted from one of my products that is in production.  The code is called every 0.1 second (10 Hz rate) and changes the PWM frequency.  The code is used to simulate the output of a flow meter. The physical flow meter outputs a variable frequency signal that is proportional to the flow of fluid through the flow meter.

if (VFDCurrentHz < 5.00)
   ' Main Pump speed is too low to generate meaningful flow values
   '
   SimProductGPM = 0.0
   SetPWM 1, 0, 1         ' 0% duty cycle so output is "OFF"
else
   ' The main pump is running so we will calculate flows based on VFD frequency
   '
   SimProductGPM    = 0.0007 * VFDCurrentHz * VFDCurrentHz + 0.0194 * VFDCurrentHz + 0.7229

   ' Generate pulse output for flow.
   '
   SetPWM 1, 5000, SimProductGPM / 60.0 * ProductPPG
endif


Best regards,

Gary Dickinson
99
Technical support / Changing STEPSPEED
« Last post by acxysty on October 13, 2019, 01:36:30 AM »
I want to increase/decrease slowly the PPS of a stepper motor without going through acceleration/decceleration phases from/to 0. Is that possible using the STEPSPEED command ?

In different topics it is said that it is possible to modify the PPS of a stepper motor using the STEPSPEED command providing this is not done during the acceleration or decelarration phases.

By doing so is the PPS be varied 'level' by level with going down to 0 each time?

Thank you in advance

Regards

Thierry

100
Technical support / Re: web page 0.htm DM32 value display
« Last post by TriRob84 on October 08, 2019, 01:56:23 AM »
Thanks for directions, I do have script for Integer and float to be displayed on build in htm pages so gonna try workout DM32 to be displayed based on that. Thanks again.
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