The invention lies in the field of simultaneous measurement of a number of variable quantities.
The invention has for its object to embody a measuring system such that a number of users can acquire permanent insight into measurement values relevant to them, while each user is nevertheless free to move at a distance from the object being subjected to measurement. For this purpose the invention generally provides a measuring system according to claim 1.
This system according to the invention makes use of the basic principle applied in paging systems. The system according to the invention can transmit measurement values in wireless manner to a relevant official. The receiver can in this way be considered a wireless measuring instrument on which the user can read the information of importance to him at any desired moment.
As is known, paging is a means of communication which is suitable for transmitting limited amounts of information directed at a specific user or group of users. For example, from GB-A-2 219 423 a paging system is known for receiving data whose value may change periodically. When used as a portable measuring instrument there is the danger of the paging communication channel becoming overloaded. To prevent this the invention as defined by claim 1 provides:
In another embodiment the measuring system comprises a signal processing unit which is connected between the input unit and the display unit and which has a memory for storing a preselected value of a measurement signal;
This embodiment enables determining of alarm limit values on either the transmitting side or on the receiving side, at exceeding of which a user or group of users must be alerted by means of light signalling, generating of an acoustic signal or generating of a control signal to a vibrator present in the receiver which makes the alarm signal tangible to the user.
It may be advisable to transmit an alarm situation relating to a particular sensor to a larger group of users other than the user who has insight into the relevant measurement values in normal conditions. A variant of the system according to the invention has in this respect the special feature that the marking means are controlled by the comparing means.
In addition, the invention provides a measuring system wherein the display means comprise two display parts, the first of which displays a measurement value and the second of which is controlled by the associated marking and displays an identification of the relevant sensor. The presentation of the measurement value can take place in numeric or analog (bar graphs) manner, while the identification of the relevant sensor can relate to a particular machine, a tunnel, a runway etc. This second display part can moreover be used for normal paging messages and for instance indicate a code, for instance "phone back".
The invention will now be elucidated with reference to the annexed drawing. In the drawing:
Measuring sensors 1, 2, 3, 4, 5 feed their output signals, which are representative of measured quantities, to an interface 6 which supplies a multiplex output signal to an input/output unit 7. The output signals coming therefrom are fed to a central processing unit or CPU 8, the output signals of which are fed to a transmitter 9 with an aerial 10. CPU 8 can further receive input signals from an adjusting unit 11 which can be operated by operating means and in which for instance alarm thresholds, limit values and other relevant data can be stored in advance by the user. The stored data relating for instance to alarm thresholds is compared in the CPU with the current values of the corresponding signals of sensors 1-5, wherein, when an alarm threshold is exceeded, a corresponding signal can be transmitted by the transmitter 9. The most recent measurement value can always be stored in a memory 12. Due to a permanent comparison between the output signal of unit 7 and memory 12 a status changing signal can only be supplied to transmitter 9 in the case of a detected difference to bring up to date the presentation of the measurement values to be described hereinafter.
The receiver according to figure 1b comprises an aerial 13 which feeds its signals to a tuning unit 14. This is tuned to the frequency transmitted by transmitter 9. The tuner 14 supplies its detected output signals to a central processing unit or CPU 15. Like the CPU 8, this CPU 15 is connected to a unit 16 in which reference settings and the like can be held, as well as to a memory 17 for the most recent measurement value. Operating means 18 can control the CPU, inter alia for displaying the data relating to one of the sensors 1-5. The CPU supplies the relevant output signals to a first display unit 19 which displays the measurement values and to a second display unit 20 which provides identification of the relevant sensor.
The system according to the invention offers the possibility that a receiver receives specific, selected information. The associated user is competent to monitor specific measurement values, while another user carrying another receiver monitors other measurement values. The CPU comprises for this purpose marking means for marking the measurement signals originating from measuring sensors 1-5. Depending on the setting of these marking means, which can take place by making use of the adjusting unit 11, a determined routing of a measurement signal can take place. A measurement signal can for instance be sent to one selected receiver, while alternatively a selected group of receivers can also receive this measurement signal. It will be apparent that the marking means thus possess a matrix function. A determination is made of incoming signals from which sensor they originate, which value they have and to which receiver they must be transmitted in accordance with the set instruction.
This matrix setting can be dynamic and depend for instance on measurement values. This can be of particular importance in alarm situations.
Figure 2 shows by way of random example a receiver 21 with an LCD screen in which the designation "MACHINE 1" identifies the relevant sensor, the designation "PRESSURE 18 BAR" indicates the pressure measured by a sensor with thereunder an LCD bar to display the corresponding value in analog manner, with thereunder in this case the designation "TEMP 49 C" as temperature value with thereunder the corresponding LCD bar. Situated right at the bottom are two energized arrow-like indications which show that the temperature displays a rising trend.
The LCD screen 22 consists of an upper first portion in which is contained an identification relating to the machine "MACHINE 1", while the lower second portion displays information relating to the measured quantities, in this case "PRESSURE 18 BAR" and "TEMP 49 C".
The reference numeral 23 in figure 1b designates an alarm signalling device, in particular a buzzer.
Situated on the underside of the receiver 21 shown in figure 2 is a keyboard 24 for entering data into the CPU 15, for instance entering alarm threshold data into the unit 16.