I'm currently using a 1760-L12BWB Series B Pico controller to control a print signal on a continuous feed process. The line speed runs anywhere between 30 & 100 fpm and I'm using a 600 ppr encoder tied into the high speed counter on the plc. The wheel on the encoder has a 1 Foot Circumference and I need the signal to output every 5 Feet regardless of the speed the line is running at. The counter setting should be set at 3000 (600ppr x 5Ft.)
The problem I'm having is that in order to get the print string spacing in spec, I have to adjust the counter setting to 2920, plus the distance between the print marks can vary by up to a half an inch, mostly on the higher line speed which is not acceptable.
According to the Pico Spec sheet, the HSCounters should be able to handle a frequency up to 5KHz. Even at 100 fpm on my application I'm only hitting 1KHz if my calculations are correct. (100fpm = 1.666667 ft/Sec x 600 ppf = 1000.0002 Pulses per Ft = 1 KHz)
Am I doing something wrong?
Is the output on this unit just not accurate enough or am I loosing pulses when I reset the counter?
The problem I'm having is that in order to get the print string spacing in spec, I have to adjust the counter setting to 2920, plus the distance between the print marks can vary by up to a half an inch, mostly on the higher line speed which is not acceptable.
According to the Pico Spec sheet, the HSCounters should be able to handle a frequency up to 5KHz. Even at 100 fpm on my application I'm only hitting 1KHz if my calculations are correct. (100fpm = 1.666667 ft/Sec x 600 ppf = 1000.0002 Pulses per Ft = 1 KHz)
Am I doing something wrong?
Is the output on this unit just not accurate enough or am I loosing pulses when I reset the counter?
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