1. The composition of the belt scale consists of four parts: weighing frame, weighing sensor, speed sensor and display instrument.
Two, the control principle of the belt scale
1. The scale is used for the quantitative feeding of scattered materials. In the process of feeding, the feeder is continuously supplied by the belt. The feeder will transport the material from the user to the silo or other feeding equipment in the future and carry on the weight test through the weighing bridge. At the same time, the speed sensor of the tail wheel is installed to carry out the speed measurement of the belt. The measured weight signal and the speed signal are sent to the MT3105P integrator to perform differential processing and show the instantaneous flow per hour per unit. According to the corresponding signal value (PID signal) of the output of the deviation size, the speed of the motor is changed by the frequency converter to change the feed amount, so as to make it with the set value. In order to complete the control of the constant feed flow. From the weighing principle, the instantaneous flow rate of the material measured by the electronic belt weigher depends on two parameters, that is, the instantaneous flow rate is equal to the material load value Q (kg/m) measured by the weighing sensor and the two parameters of the velocity value V (m/s) measured by the speed sensor. That is, w (T) =qv can be seen and the speed sensor is measured. The accuracy and stability of measurement are equally important to the accuracy and stability of weighing sensors. At present, the accuracy of weighing sensors is generally increased to a few thousandths, and the accuracy of the speed sensor is mostly in a few thousandths, so improving the accuracy of the speed sensor is one of the ways to improve the accuracy of the electronic belt scale system.
2, starting feeder: press the start button in the field operation box 1SB, 1KA1, 1KA3 relay at the same time, the frequency converter starts the signal closed, at this time the feeder and the motor fan start running, the running indicator 1HL2 light (when the proportioning scale fails this light flashes), through the spot speed knob 1RP to make the frequency converter output current change and The motor speed is also changing. During the running process, it is found that the stop button should be pressed by 1SB2, the belt should be adjusted, or the machine can be switched on. The central control boot usually talks about the switch switch to the central control position. The panel's ready lamp must be on the bright side, otherwise it will not be able to turn on the middle control or damage the lamp.
Three, setting of parameters and calibration of weighing feeder
1, calibration of instrument parameters: after the belt tends to be stable for a period of time, the parameters of MT3105 instrument parameters can be set, such as the position of the small number point of the input instrument, the unit and capacity of the scale, the capacity of the sensor and the sensitivity of the sensor, and the length of the belt for one week. Initial use requires input of original parameters, and normal use usually does not need to be altered at will.
2. The calibration of weighing feeder: first obtain the test cycle, then carry on the zero point calibration, the zero point can be calibrated after the stable, the interval calibration can be divided into physical calibration, chain code calibration, hanging code calibration and other methods, using the special AUTO MAT (automatic material calibration) software of Ramsay, can automatically correct the belt scale. After the N value is calibrated, the weighing value can be weighed and accumulated.
Four, drift of zero point and drift of interval, the drift of zero point is generally related to the conveying system, and the reasons for zero drift are:
A. weighed the dust and aggregate on the bridge.
B. materials and clutter cards are in the weighed bridge.
The C. belt conveyer has sticky material.
D. belt tension is not uniform.
E. because of the temperature characteristics of materials and the long-term use of belts, the belt is stretched.
F. failure of electronic measurement components.
The severe overload of the g. load sensor.
The cause of the interval drift
Change of belt tension of conveyer
(2) the change of the sliding or its diameter of a velocity measuring drum