I made a recent hardware change to a flow meter system and have come up with a strange problem. I hope someone can lead me in the right direction.
The counter - Veeder-Root (Form 797586-220)is connected to an output on a ML1100. A pulse from a flow meter is sensed by an input on the ML1100 and is used to increment an internal counter. In parallel with the internal counter is the output to the digital counter. The counter sends one pulse per litre. The flow rate is 17,000 litres/hour (approximately 4.722 pulses / second)
Originally, the counter was connected directly to the meter (no PLC in the way) and would increment every litre.
Currently, the counter sometimes increments by litre, but also skips from time-to-time.
I tried connecting the counter in parallel with the PLC input with similar results.
I should add that the internal counter updates perfectly.
I was thinking of installing a pull-down resistor between the pulse and ground. Any other suggestions?
The counter - Veeder-Root (Form 797586-220)is connected to an output on a ML1100. A pulse from a flow meter is sensed by an input on the ML1100 and is used to increment an internal counter. In parallel with the internal counter is the output to the digital counter. The counter sends one pulse per litre. The flow rate is 17,000 litres/hour (approximately 4.722 pulses / second)
Originally, the counter was connected directly to the meter (no PLC in the way) and would increment every litre.
Currently, the counter sometimes increments by litre, but also skips from time-to-time.
I tried connecting the counter in parallel with the PLC input with similar results.
I should add that the internal counter updates perfectly.
I was thinking of installing a pull-down resistor between the pulse and ground. Any other suggestions?