Signaling, dozing and control system

Signaling  limits of weighting mass.
Each scale of MENSOR company is equipped with the indication of signaling limits of weighing mass system  illustrated on the display of the scale.
On the left side of the display scale is vertical line  placed at the bottom completed  with  "LO", from the top with "HI". After start function of signal levels and programming, both of values:   the mark  “LO” is indicated for the load value smaller threshold – the mark “HI” for the value bigger from the top threshold   (left semi-circle in the upper right corner of the display). For the load between “LO”  and “HI” is indicated of horizontal line. Its position   is proportional to the load.  This function works fine in normal weight. The values of "LO" and "HI" are always  positive.

Fig. 1 Display with the mark: “LO” and “HI”

Optionally, the scale can be equipped with light-emitting diodes in the front panel acting (like) as characters, "" LO "and" HI ".
  The scale can be optionally equipped with a horn, signaling indications from the interval <"LO", "HI">. Also, the scale can be optionally  equipped   with two independent  relays shorted or open  properly when crossing levels "LO" and "HI". Sounder and relay outputs can operate only when the scale has power supply. In case battery  supply,  only indications on the display are possible.
Threshold values can be put into the scale from the computer, or by placing appropriate mass on the pan. Optionally, you can also enter values from the keyboard scale.

The use of signaling system limits of mass described above  can be varied. For example, this system performs the functions of the measured three-position controller where the interval between "LO" and "Hi" is a dead zone and the level of control, is the set point by “LO”  and “HI”, Figure 2

Fig 2 Diagram of the three-position controller

A simple application of signaling limits of weighting mass system is connected to the scale by  a conspicuous light lamp  indicating  one limit value  fig. 3, or two values: "LO" and "Hi" fig. 4

Fig. 3 The scale type WM3P3 30x40 with one lamp indicating a limit threshold value

Fig. 4 The scale type WM3P3 30x40 with two lamps indicating a limit threshold value

          Electronic scale of MENSOR company equipped with an  signaling limits of weighting system can also work  as a  controller   segregated for good elements  with correct weight and  the wrong, which does not meet the criteria established mass  fig. 5.  Elements weighing on the first feeder having incorrect  mass, below “LO” ,  fall into the first container as wrong, but those elements which weighing more than "HI" fall into the container as "good".
In the case of normal mass-weighted elements on the first feeder the scale is  controlled by relays actuator such as a pneumatic cylinder, which moves  the second feeder to the first one to get weighed elements and send them to a container of  "good" elements.

Fig. 5 Diagram of elements selection according to criterion based on the measurement of  mass

A typical application of scale equipped with the  limits signaling system of mass is portioning of loose materials  fig. 6.  Mass of the bag, which is filled with loose material is weighted by the inductive transmitter of mass . At a given value of "HI" with the relay and actuator the scale shuts of  material from the tank into the bag. In this case, the dosing process, restart manually after removing the filled bag and replace it with an empty bag.

Fig. 6  Dosing system for loose materials

Example control flow of loose material shows on Figure 7.   Loose material falls on the inclined plate connected with inductive measuring transmitter. The force component acting on the plate is the input of the scale  and it  value depends on the flow of material falling on the plate. Too high flow causes the signal  "HI" and scale through the relay closes the valve located at the outlet of the tank. In the case of small flow metering valve is little open.

Fig. 7  Diagram of the flow control of loose materials

A common use  of signaling limits of weighing mass system  is control the content of gas in the cylinder. In the case of gas supply devices requiring continuous operation is required  signaling of minimum gas in the cylinder, to replace it.
Putting on the scale cylinder equipped with a signaling system  we solves this problem Figure 8 In general, is required special design for mounting high cylinder on the platform of scale  -   MENSOR company can solve such kind of problem.

Fig. 8 Signaling the minimum content of the gas in the cylinder

A similar example of a weighting to dispense bulk material as shown in Figure 5 is the smallest mass dispensing with vibratory feeder Fig. 9. This feeder is poured loose mass on the pan until it reaches before programming the  value "HI". At this point, vibrating feeder is turned off and take a weighed mass from the pan - it can be a container, replaced by a blank. When you turn on the vibrating feeder repeating the dispensing cycle. In contrast to the example of Figure 5, we have here a much slower due to the filling of the container that is result  of principle  a vibrating feeder.

Fig. 9 Dosing system for loose materials with vibrating feeder