This disclosure relates to a rate parameter indicator which uniquely allows extremely accurate measuring and indicating of a rate parameter at low rates due to provision of a smooth linear signal to an indication meter circuit. The system incorporates a low voltage drift switching circuit which is coupled to a constant-width pulses, the frequency of which is proportional to a rate parameter. A meter jitter minimizing circuit is electrically coupled to the low voltage drift switching circuitry, as well as the constant voltage source, and includes an averaging circuit which allows the meter jitter minimizing means to provide the aforementioned smooth linear signal to the indication meter circuit in a unique manner.
This application is a division of my copending application for Letters Patent of the United States, Ser. No. 879,716, filed Nov. 25, 2969, now Pat. No. 3,638,115, for Rate Parameter Indicator Having Meter Movement Smoothing At Low Rates.
A calibrated tuneable monitor for use with multi-row planting apparatus includes means for sensing the number of seeds delivered to furrows formed in a field and controlling an indicator to give a visual readout to the operator of the planting apparatus as to whether the number of seeds planted is at least equal to a predetermined minimum value which is preset by a selector dial. The seed monitor system has a DC coupled monostable circuit for producing a pulse of given pulse width for each pulse produced by a seed sensor. The pulse from the DC coupled monostable circuit is then integrated and formed into a voltage which is proportional to the rate at which pulses are received. This voltage is then compared in a voltage comparator circuit to control the operation of an indicator.
A system for monitoring the operation of a plurality of rotating-shaft machines, including a switchable meter to indicate the shaft speed of any one of these machines. Each machine has a monitoring circuit including respective visual warning branch circuits to indicate if the machine shaft falls below a first preset speed and then to indicate if the machine shaft falls below a second preset speed, with provision for sounding an audible alarm. The system has a single power supply, switchable meter, audible alarm control circuit and warning reset circuit, and identical monitor modules for the respective machines to be monitored. Each module has an external sensor, consisting of a pickup coil and a magnet assembly attached to the rotating shaft of the monitored machine; a high-gain integrated circuit amplifier to amplify the pulses from the sensor; circuitry to convert the pulses to a D.C. voltage proportional to shaft speed; visual warning and alarm lamps; a switch to connect the audible alarm to the module or optionally to disconnect it; separate high-gain integrated circuit amplifiers to control the indicating meter, visual warning, and visual/audible alarm; and multi-turn potentiometers, accessible from a common front panel to control sensitivity, speed range, meter circuit gain, and set points in percent of normal speed for the warning and alarm circuits.
