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unable to obtain maximum scan rate
« on: April 15, 2017, 03:26:17 PM »
I have been  adding functions on to my Pokeys 57E , and the Device load went up and up
Now the Device Load Status screen is at 100 and the app says ' Maximum scan rate cannot be obtained '.  

Refer to attached screenshots  for hardware , software and configuration data.
i am running the latest Mach4 unlicensed, on a Mac Boot Camp Drive. (I5 1.4 GZ).

when I de-activate the pulse engine the 'load' drops to under 100 percent and
the message goes away and device load status drops to 78 percent.

See ' Device load status  window’ . note the 'drop' in the graph. thats when i turned
        the pulse engine off and then on. '

I need every inout and output i can get ,  i am using 48 of the exBus outputs
three high speed and one ultra high speed encoder and a 4 x 8 key-input matrix
plus the pulse engine.

question zero
is this a big problem ? does this  mean trouble when i try to make chips.
or can i ignore the 'warning'.

question one:
is the 57CNC faster ? will it manage the above load any better
or will i need a second 57E to handle some of the IO.

question two :
Will Mach4 handle Dual 57's,  one for IO and one for pulse ?

question three:
are there any tricks to reduce load ?
i don’t need high speed on the matrix inputs
or on the 48 outputs ?


thanks in advance
« Last Edit: April 15, 2017, 03:28:44 PM by machiner »
Re: unable to obtain maximum scan rate
« Reply #1 on: April 16, 2017, 12:00:05 PM »
This may be irrelevant to your question, but I noticed all error inputs are lit up, and I saw that yesterday. You have "external pulse generator" selected, but NOT "Extended I/O".  I ran into that yesterday when things wouldn't work.  The 57cnc manual says "Pulse generator options: PoKeys57CNC contains an external pulse generator on-board, thus external pulse generator option with ‘Extended IO’ must be selected."
Re: unable to obtain maximum scan rate
« Reply #2 on: April 16, 2017, 05:08:54 PM »
Thanks for your response.

I Have a 57E, Not a 57CNC. For step drivers I use the PoExtBusOC16CNC,
which  has no External Outputs. I could set it for 8 step motors but I only use 4.


I trust someone will comment if This pulse engine configuration is incorrect for my setup.
I will run some tests on alternate configurations, and notify if that helps at all.
Re: unable to obtain maximum scan rate
« Reply #3 on: April 16, 2017, 06:13:46 PM »
Missed that detail....  Good luck with it.

Offline NeoTO

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Re: unable to obtain maximum scan rate
« Reply #4 on: May 19, 2017, 01:11:16 AM »
The maximum scan rate is needed to get the 'normal encoders' (which can be connected to any pin) to be processed in time. However, you shouldn't be able to detect any issue with the non-maximum scan rate in your setup.
Are you using Mach3/Mach4 or Pulse engine on its own?
www.poscope.com home of PoKeys USB HID, IO, USB, Ethernet controler and PoScope USB PC oscilloscope
Re: unable to obtain maximum scan rate
« Reply #5 on: May 24, 2017, 11:00:21 AM »
Thanks for your reply. There is no noticeable problem with the Pokeys unit, I was just unsure of the meaning of the maximum scan rate warning. I am using Mach4 on a 2 Axis Lathe.