HIGH SPEED COUNTER LIMITS

[CMS]

Hi

Is the 4khz limit on the MX series purely due to the opto-isolated inputs or is there some other reason??

Cheers

CMS

[support]

yes, the optocoupler has a slower frequency response than the CMOS logic circuit using in the T100MD+ PLC. So even though the CPU HSC can operate up to 10Khz, the input optocoupler could not operate at that switching speed.

[CMS]

Would it be possible to replace the optoisolator with one that has a faster response time, I need all the functions of a T100MX-3224R .  But I need to have a high speed counter to measure frequancy up to about 8Khz.  

I would require multiple units with such capabilitys, could I get the factory modified or would I have to modify them myself?

Cheers

CMS

[support]

The optocoupler used on the T100MX is bi-directional type with part number LTV814 or PC814. Since these are all socketed type you can replace with a pin compatible part that is faster. However, we can't recommend any part number without first testing it ourselve.

I did a quick search in the NET and found the following item:


http://dspace.dial.pipex.com/isocom/isk620.htm#electrical

It appear to be pin compatible with PC814, but a test is required to ensure that the current transfer ratio is sufficient to drive the PLC input.

Please contact the supplier for rise time/fall time data to determine whether it is much faster than PC814.