Frequently Asked Questions about FV Converters

When a reflective sticker is applied to the axis, the signal detected by photoelectric sensors such as the LG-916 and LG-930 has a low pulse count per second. Depending on the rotation speed to be measured, this can become extremely low relative to the frequency range of the FV conversion circuit, resulting in an output voltage as described in the question.

Explanation
TM-2130 and FV-1100 utilize the FV conversion circuit (frequency/voltage conversion circuit) to convert the input signal frequency into a proportional voltage. The integrator circuit charges when the input pulse is at a high level and discharges when it is at a low level. As the frequency of the input pulse increases, the number of charging instances increases, resulting in a longer overall charging time, which causes the output voltage to rise. Conversely, when the frequency decreases, the discharge time becomes longer than the charging time, leading to a decrease in output voltage.
The speed of charging and discharging is faster with a smaller time constant, and the difference in charging and discharging voltage (ripple) per pulse becomes larger. This ripple is minimal at high input frequencies but becomes more pronounced at lower frequencies.
Photoelectric detectors like LG-916 and LG-930 only output signals based on the number of reflective seals applied per rotation, making the input frequency likely to be low, resulting in the condition described in the question. It is necessary to calculate the input frequency from the operating rotation range and confirm whether it can be used at more than 10% of the frequency range for FV conversion.
The catalog for TM-2130 lists the amount of ripple in output voltage when the frequency is at 1% of the frequency range.