Patent Description:
In <CIT>, a network for FA (frequency analysis) is disclosed. Such an FA network is provided in industrial equipment in which robots and the like are used. Such an FA network includes a master and a plurality of slaves. The master and the plurality of slaves transmit and receive data to and from each other in a wireless manner.

<CIT> discloses a method for scanning channels to determine channel space states. A wireless remote transceiver continuously or repeatedly scans the channel space and communicates the channel space states with a wireless display device. When interference in the channel used to transmit content to the wireless display is detected during a scan, a graphical representation of the channel space state is displayed in the wireless device. A user may select a channel with a lower likelihood of interference based on the displayed scanning results. <CIT> is considered closest prior art document.

<CIT> discloses systems and methods for deploying, controlling, and managing wireless communication equipment.

A <NUM> frequency band (ISM band) is generally open to the public. The number of wireless devices that perform data communication using the <NUM> frequency band is increasing. Therefore, the possibility that interference between radio waves will occur in the <NUM> frequency band is becoming higher.

In the case that a user who manages industrial equipment newly installs a wireless device in the industrial equipment, it is necessary to set the frequencies used by the wireless device while avoiding frequencies that are already being used. Accordingly, in the case that a plurality of channels are used, it is necessary for the user to investigate which frequencies are not being used. The frequencies that are not being used are also referred to as free frequencies. Such an operation is troublesome for the user to perform.

The present invention has the object of solving the aforementioned problem.

This problem is solved by the display systems according to claim <NUM> and <NUM>. Preferred embodiments of the invention are evident from the dependent claims.

According to the present invention, the user can easily be made aware of the free frequencies existing within a predetermined frequency band.

The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which preferred embodiments of the present invention are shown by way of illustrative example.

<FIG> is a diagram showing the configuration of an industrial wireless communication system <NUM> in which a display system <NUM> is used. In the industrial wireless communication system <NUM>, there are provided a single computer <NUM>, a plurality of base wireless devices <NUM>, a plurality of remote wireless devices <NUM>, and the display system <NUM>. The industrial wireless communication system <NUM> is equipped with a plurality of networks <NUM>. A single base wireless device <NUM> and a plurality of remote wireless devices <NUM> are provided in one of the networks <NUM>. The single computer <NUM>, the plurality of base wireless devices <NUM>, and the display system <NUM> are connected over wires or wirelessly in order to enable communication therebetween. The wired connection may be a fieldbus <NUM>. The wireless connection may be by way of short-range wireless communication. The plurality of remote wireless devices <NUM> are synchronously connected to the single base wireless device <NUM>.

The computer <NUM> is capable of monitoring and controlling the industrial equipment. Although not limited to this feature, the computer <NUM> is constituted, for example, by a PLC (programmable logic controller). The computer <NUM> is capable of carrying out communication with other devices using an input/output interface (not shown).

The base wireless devices <NUM> are also referred to as master wireless devices. The base wireless devices <NUM> are capable of carrying out communication with the computer <NUM> and the display system <NUM> using an input/output interface (not shown) or a first communication unit (not shown). The base wireless devices <NUM> are capable of carrying out communication with the remote wireless devices <NUM> using a second communication unit (not shown) that carries out wireless communication in a frequency band of <NUM>.

The remote wireless devices <NUM> are also referred to as slave wireless devices. The remote wireless devices <NUM> are each provided in each of a plurality of machinery <NUM> (see <FIG>) that make up the industrial equipment. As such machinery <NUM>, although not limited thereto, there may be cited sensors, valves, and the like. The remote wireless devices <NUM> are each equipped with a communication unit (not shown) that carries out wireless communication in a frequency band of <NUM>. By using such a communication unit, the remote wireless devices <NUM> are capable of communicating with the base wireless devices <NUM>. In the example shown in <FIG>, one piece of the machinery <NUM> is provided for each one of the remote wireless devices <NUM>. However, a plurality of the machinery <NUM> may be provided for each one of the remote wireless devices <NUM>.

The base wireless devices <NUM> and the remote wireless devices <NUM> communicate with each other by way of a frequency hopping method. More specifically, the base wireless devices <NUM> and the remote wireless devices <NUM> switch between hopping frequencies at a predetermined hopping cycle to thereby transmit and receive data.

<FIG> is a block diagram showing the display system <NUM> according to the present embodiment. The display system <NUM>, for example, includes a personal computer or a mobile terminal (a tablet type terminal, a smartphone or the like). The personal computer or the mobile terminal is capable of communicating with other devices over wires or wirelessly. <FIG> shows a state in which the display system <NUM> which includes the personal computer is connected to another device by the fieldbus <NUM>. The display system <NUM> may be provided in the base wireless devices <NUM>. Further, the display system <NUM> may be configured by a plurality of devices. For example, the display system <NUM> may be constituted by a personal computer or a mobile terminal, and the base wireless devices <NUM>. In this case, the personal computer or the mobile terminal and the base wireless devices <NUM> may communicate with each other over wires or wirelessly. Further, the display system <NUM> may include a personal computer and a frequency measurement device (a frequency counter, a spectrum analyzer, or the like).

The display system <NUM> is equipped with an operation unit <NUM>, a computation unit <NUM>, a storage unit <NUM>, a display unit <NUM>, an input/output interface <NUM>, and a reception unit <NUM>. Hereinafter, an embodiment will be described for a case in which the display system <NUM> comprises a personal computer. The operation unit <NUM>, the computation unit <NUM>, the storage unit <NUM>, the display unit <NUM>, the input/output interface <NUM>, and the reception unit <NUM> may be constituted by a plurality of devices. For example, the personal computer may be equipped with the operation unit <NUM>, and the display unit <NUM>, and the base wireless devices <NUM> may be equipped with the computation unit <NUM>, the storage unit <NUM>, the display unit <NUM>, and the reception unit <NUM>.

The operation unit <NUM> includes, for example, at least one of a keyboard, a mouse, a touch pad, a touch panel, and a microphone. The operation unit <NUM> is a human-machine interface in order for the user to input data and instructions to the display system <NUM>. The data input by the operation unit <NUM> is stored in the storage unit <NUM>.

The computation unit <NUM> includes a processor, and more specifically, a processing circuit such as a CPU or the like. The computation unit <NUM> administers the control of the display system <NUM> in its entirety. By executing programs stored in the storage unit <NUM>, the computation unit <NUM> functions as a measurement unit <NUM> and a control unit <NUM>. The measurement unit <NUM> measures frequencies and power levels of radio waves that propagate around the periphery of the wireless devices. The control unit <NUM> determines non-recommended frequencies <NUM> (see <FIG>, etc.) and recommended frequencies <NUM> (see <FIG>, etc.), and causes the display unit <NUM> to display the non-recommended frequencies <NUM> and the recommended frequencies <NUM>. The non-recommended frequencies <NUM> refer to frequencies that are being used within the <NUM> frequency band. The recommended frequencies <NUM> refer to frequencies that are not being used within the <NUM> frequency band. Moreover, at least a portion of the computation unit <NUM> may be realized by an integrated circuit such as an ASIC, an FPGA, or the like. Further, at least a portion of the control unit <NUM> may include an electronic circuit containing a discrete device. Moreover, the measurement unit <NUM> may include a frequency measuring device.

The storage unit <NUM> includes a volatile memory and a non-volatile memory. As the volatile memory, for example, there may be cited a RAM or the like. As the non-volatile memory, for example, there may be cited a ROM, a flash memory, or the like. The volatile memory is used as a working memory for the processor, and temporarily stores data and the like necessary for performing processes or calculations. In the non-volatile memory, there are stored, for example, programs, tables, maps, and the like. At least a portion of the storage unit <NUM> may be provided in the processor, the integrated circuit, or the like as described above.

The non-volatile memory of the storage unit <NUM> stores frequency information <NUM>. For example, the frequency information <NUM> is information in which the numbers of channels (channel numbers) assigned to the <NUM> frequency band and the occupied frequency band information are associated with each other. The channel numbers are numbers assigned to the channels assigned to the <NUM> frequency band. The respective channels include occupied frequency bands of <NUM>. The occupied frequency band information is information in relation to each of the occupied frequency bands. For example, the occupied frequency band information includes a center frequency of the occupied frequency bands, an upper limit frequency of the occupied frequency bands, and a lower limit frequency of the occupied frequency bands. For example, in the case of a wireless LAN, the communication standard of which is specified by IEEE <NUM>. 11b, then as shown in <FIG>, the frequency information <NUM> associates the channel numbers of <NUM> ch to <NUM> ch with the occupied frequency bands of the respective channels. The same consideration applies to other wireless communication standards. Moreover, the non-volatile memory of the present embodiment stores the channels and the occupied frequency bands of the wireless LAN specified by IEEE <NUM>. 11b, as the frequency information <NUM>. There are cases in which the number of channels used within the <NUM> frequency band are determined independently depending on the country. Frequency information <NUM> is set according to the country in which the industrial wireless communication system <NUM> is provided.

The display unit <NUM> includes a monitor such as a liquid crystal display or the like. The display unit <NUM> displays an image <NUM> (see <FIG>, etc.) in response to a display command output from the control unit <NUM>. For example, the display unit <NUM> displays the image <NUM> in which the non-recommended frequencies <NUM> and the recommended frequencies <NUM> are included.

The input/output interface <NUM> includes an interface (for example, a connector, a modem, or the like) for the purpose of realizing a fieldbus connection.

The reception unit <NUM> is constituted, for example, by an antenna and a communication module. The reception unit <NUM> receives radio waves that propagate in a space in which the industrial equipment is installed.

<FIG> is a flowchart showing a first display process performed by the display system <NUM>. <FIG> is a diagram showing measurement results of power levels for each of the respective frequencies. <FIG> are diagrams showing examples of the image <NUM> displayed by the display unit <NUM> in the first display process. Prior to newly installing a wireless device in the industrial equipment, the user uses the display system <NUM> to investigate frequencies that are not being used. The user uses the operation unit <NUM> to perform input operations of data such as a set time period and a power threshold value or the like. In accordance with the input operations made by the user, the operation unit <NUM> outputs data such as the set time period and the power threshold value or the like to the storage unit <NUM>. The storage unit <NUM> stores the data output from the operation unit <NUM>. Moreover, the storage unit <NUM> may store the set time period and the power threshold value in advance. When the user performs a predetermined operation on the operation unit <NUM>, the display system <NUM> initiates the first display process described below.

In step S1, the reception unit <NUM> receives radio waves that propagate in a space in which the industrial equipment is disposed. The measurement unit <NUM> measures, within the input set time period, the frequencies and the power levels of the radio waves received by the reception unit <NUM>. When the measurement is completed, the process proceeds to step S2.

In step S2, on the basis of the measurement results of the measurement unit <NUM>, the control unit <NUM> identifies the frequencies of the radio waves the power of which is greater than or equal to the power threshold value, and the frequencies of the radio waves the power of which is less than the power threshold value. The control unit <NUM> determines the frequencies of the radio waves the power of which is greater than or equal to the power threshold value, as being the non-recommended frequencies <NUM>. The control unit <NUM> determines the frequencies of the radio waves the power of which is less than the power threshold value, as being the recommended frequencies <NUM>. In the example shown in <FIG>, the power levels of the radio waves having frequencies of <NUM>, <NUM>, and <NUM> are greater than or equal to the power threshold value (Vth). In the example shown in <FIG>, the control unit <NUM> determines the frequencies of <NUM>, <NUM>, and <NUM> as being the non-recommended frequencies <NUM>. The control unit <NUM> determines the frequencies other than the frequencies of <NUM>, <NUM>, and <NUM> as being the recommended frequencies <NUM>. When step S2 is completed, the process proceeds to step S3.

In step S3, the control unit <NUM> causes the non-recommended frequencies <NUM> and the recommended frequencies <NUM> to be displayed on the display unit <NUM> so as to be distinguishable from each other. The display unit <NUM> displays the image <NUM> in response to a display command output from the control unit <NUM>. An example of the image <NUM> is shown in <FIG>. A graph is shown in the image <NUM>. In such a graph, respective frequencies from <NUM> to <NUM> are arranged in the horizontal direction, and the non-recommended frequencies <NUM> and the recommended frequencies <NUM> are shown separately in the vertical direction. In the image <NUM> shown in <FIG>, among the frequency bands of <NUM> to <NUM>, the frequencies excluding the frequencies of <NUM>, <NUM>, and <NUM> are represented by solid lines. The frequencies displayed by the solid lines are the recommended frequencies <NUM>. The bandwidth of each of the recommended frequencies <NUM> is <NUM>. On the other hand, the frequencies of <NUM>, <NUM>, and <NUM> are represented by dashed lines. The frequencies displayed by the dashed lines are the non-recommended frequencies <NUM>.

As shown in <FIG>, as one example thereof, the display unit <NUM> displays the non-recommended frequencies <NUM> by dashed lines and the recommended frequencies <NUM> by solid lines. However, the display unit <NUM> may display the non-recommended frequencies <NUM> and the recommended frequencies <NUM> in different colors. Alternatively, the display unit <NUM> may display each of the non-recommended frequencies <NUM> and the recommended frequencies <NUM> by numerical values.

The display unit <NUM> may display the non-recommended frequencies <NUM> and the recommended frequencies <NUM> in different display forms. For example, as shown in <FIG>, the display unit <NUM> may display the non-recommended frequencies <NUM> as convex portions <NUM> that project toward the plus side of the vertical axis. Further, the display unit <NUM> may display the recommended frequencies <NUM> as flat portions <NUM> that overlap with the horizontal axis. Conversely, as shown in <FIG>, the display unit <NUM> may display the recommended frequencies <NUM> as convex portions <NUM> that project toward the plus side of the vertical axis. Further, the display unit <NUM> may display the non-recommended frequencies <NUM> as flat portions <NUM> that overlap with the horizontal axis. In this case, the display unit <NUM> may switch between and display the image <NUM> shown in <FIG> and the image <NUM> shown in <FIG>. Switching between the images <NUM> may be carried out by an operation performed by the operation unit <NUM>.

According to the first display process, frequencies that are not being used in the industrial equipment are displayed on the display unit <NUM>. Therefore, the user can easily be made aware of the free frequencies existing within a predetermined frequency band, for example, the <NUM> frequency band.

The frequencies that are used change from moment to moment. Therefore, there may be cases in which the measured frequencies differ depending on the timing at which the measurements in step S1 of the first display process are performed. Thus, in the second display process, in the case that a predetermined number or more of the non-recommended frequencies <NUM> exists within the occupied frequency bands corresponding to the channels, all of the frequencies included within the occupied frequency bands corresponding to such channels are displayed as the non-recommended frequencies <NUM>. The power levels of the non-recommended frequencies <NUM> are greater than or equal to the power threshold value. As a result, it is possible to prevent the frequencies included within the frequency bands that are already being used in the industrial equipment from being erroneously determined as the recommended frequencies <NUM>.

<FIG> is a flowchart showing a second display process performed by the display system <NUM>. <FIG> is a diagram showing measurement results of power levels for each of the respective frequencies. <FIG> is a diagram showing one example of the image <NUM> displayed by the display unit <NUM> in the second display process. The processes of step S11 and step S12 shown in <FIG> are the same as the processes of step S1 and step S2 shown in <FIG>. Therefore, hereinafter, a description will be given of the processes of steps S13 to S15 in which the second display process differs from the first display process.

In step S13, the control unit <NUM> reads out the frequency information <NUM> that is stored in the storage unit <NUM>. The control unit <NUM> determines whether or not there is a relationship between the non-recommended frequencies <NUM> determined in step S12 and the occupied frequency bands associated with the channels indicated by the frequency information <NUM>. For example, the control unit <NUM> determines the number of the non-recommended frequencies <NUM> included within each of the occupied frequency bands. The control unit <NUM> determines the presence or absence of occupied frequency bands in which a predetermined number of the non-recommended frequencies <NUM> is included. The predetermined number may be stored in advance in the storage unit <NUM> or may be set by the user. In the case of there being an occupied frequency band including the predetermined number of the non-recommended frequencies <NUM> (step S13: YES), the process proceeds to step S14. On the other hand, in the case of there not being an occupied frequency band including the predetermined number of the non-recommended frequencies <NUM> (step S13: NO), the process proceeds to step S15.

In step S14, the control unit <NUM> identifies the occupied frequency bands in which the predetermined number of the non-recommended frequencies <NUM> is included. The control unit <NUM> determines that all of the frequencies included within the identified occupied frequency bands are the non-recommended frequencies <NUM>. As is well known, the frequency bands from <NUM> to <NUM> include the respective channels from <NUM> ch to <NUM> ch. The respective channels include twenty-two frequencies which are partitioned by <NUM> each. In the example shown in <FIG>, among the frequencies included within a <NUM> ch occupied frequency band (from <NUM> to <NUM>), the power levels of eighteen of the frequencies are greater than or equal to the power threshold value. In the case that a numerical value of less than eighteen is set as the predetermined number, the control unit <NUM> determines that all of the frequencies included within the <NUM> ch occupied frequency band are the non-recommended frequencies <NUM>. When step S14 is completed, the process proceeds to step S15.

In step S15, the control unit <NUM> causes the non-recommended frequencies <NUM> and the recommended frequencies <NUM> to be displayed on the display unit <NUM> so as to be distinguishable from each other. In response to a display command output from the control unit <NUM>, for example, the display unit <NUM> displays the image <NUM> shown in <FIG>. In the image <NUM> shown in <FIG>, at least one of the recommended frequencies <NUM> included within the frequency bands from <NUM> to <NUM> is displayed by a solid line. However, in the image shown in <FIG>, the <NUM> ch occupied frequency band (from <NUM> to <NUM>) and the frequency of <NUM> are not displayed by solid lines. In the image shown in <FIG>, the <NUM> ch occupied frequency band (from <NUM> to <NUM>) and the frequency of <NUM> are displayed by dashed lines as the non-recommended frequencies <NUM>.

According to the second display process, in the case that a certain channel is being used, even if some of the frequencies included within the occupied frequency bands of the channel are not detected at the time of measurement, all of the frequencies included within the occupied frequency bands can be determined as being the non-recommended frequencies <NUM>. Accordingly, it is possible to prevent the frequencies that are already being used in the industrial equipment from being erroneously determined as the recommended frequencies <NUM>.

The third display process is a process in which the second display process is simplified. According to the third display process, in the case that the difference between two of the non-recommended frequencies <NUM> is less than or equal to a predetermined difference (MHz), all of the frequencies between the two non-recommended frequencies <NUM> are displayed as being the non-recommended frequencies <NUM>.

<FIG> is a flowchart showing the third display process performed by the display system <NUM>. The processes of step S21 and step S22 shown in <FIG> are the same as the processes of step S1 and step S2 shown in <FIG>. Therefore, hereinafter, a description will be given of the processes of steps S23 to S25 in which the third display process differs from the second display process.

In step S23, in the case that a plurality of the non-recommended frequencies <NUM> exist, the control unit <NUM> determines the presence or absence of two of the non-recommended frequencies <NUM> for which a frequency difference therebetween is less than or equal to a predetermined difference. Moreover, the predetermined difference may be stored in advance in the storage unit <NUM>. The predetermined difference may be set by the user. In the case of there being two of the non-recommended frequencies <NUM> for which the frequency difference therebetween is less than or equal to the predetermined difference (step S23: YES), the process proceeds to step S24. On the other hand, in the case of there not being two of the non-recommended frequencies <NUM> for which the frequency difference therebetween is less than or equal to the predetermined difference (step S23: NO), the process proceeds to step S25.

In step S24, the control unit <NUM> makes the following determination concerning two of the non-recommended frequencies <NUM> for which the frequency difference therebetween is less than or equal to the predetermined difference. More specifically, the control unit <NUM> determines that all of the frequencies between the two non-recommended frequencies <NUM> are also the non-recommended frequencies <NUM>. When step S24 is completed, the process proceeds to step S25.

In step S25, the control unit <NUM> causes the non-recommended frequencies <NUM> and the recommended frequencies <NUM> to be displayed on the display unit <NUM> so as to be distinguishable from each other. In response to a display command output from the control unit <NUM>, the display unit <NUM> displays the non-recommended frequencies <NUM> and the recommended frequencies <NUM> so as to be distinguishable from each other.

According to the third display process, in the case that the difference between the two of the non-recommended frequencies <NUM> is less than or equal to the predetermined difference, all of the frequencies between the two non-recommended frequencies <NUM> are determined as being the non-recommended frequencies <NUM>. Accordingly, it is possible to prevent the frequencies that are already being used in the industrial equipment from being erroneously determined as the recommended frequencies <NUM>.

<FIG> is a flowchart showing a fourth display process performed by the display system <NUM>, according to the claimed invention. <FIG> is a diagram showing results of measurement of power levels performed periodically. <FIG> is a diagram showing one example of the image <NUM> displayed by the display unit <NUM> in the fourth display process. In the same manner as in the first to third display processes, the user uses the operation unit <NUM> to perform input operations of various data. Moreover, as data unique to the fourth display process, there are a maximum value Nmax of the number of measurements and a degree threshold value. The operation unit <NUM> outputs, to the storage unit <NUM>, data such as the maximum value Nmax and the degree threshold value input by the user. When the user performs a predetermined operation on the operation unit <NUM>, the display system <NUM> initiates the fourth display process described below. In the present specification, a degree of usage is the number of times of being used within a certain period of time. The degree threshold value is a threshold value of the degree of usage.

In step S31, the measurement unit <NUM> sets a count number N to <NUM>. In step S32, in the same manner as in step S1 of <FIG>, the measurement unit <NUM> measures, within an input set time period, the frequencies and the power levels of the radio waves received by the reception unit <NUM>. In step S33, the measurement unit <NUM> adds <NUM> to the count number N. In step S34, the measurement unit <NUM> determines whether or not the count number N is greater than or equal to the maximum value Nmax. In the case that the count number N is greater than or equal to the maximum value Nmax (step S34: YES), the process proceeds to step S35. On the other hand, in the case that the count number N is not greater than or equal to the maximum value Nmax (step S34: NO), the process returns to step S32. In other words, in the fourth display process, the process of step S32 is performed for a number of times set by the user. The process of step S32 is performed periodically. Further, a time interval between an nth measurement and an (n + <NUM>)th measurement is on the order of <NUM> [µs] to <NUM> [ms]. The storage unit <NUM> stores the measurement results for each measurement.

In step S35, the control unit <NUM> reads out each of the measurement results of step S32 from the storage unit <NUM>. Among the frequencies of the radio waves the power levels of which are greater than or equal to the power threshold value, the control unit <NUM> determines that the frequencies with a degree of usage greater than or equal to the degree threshold value, as being the non-recommended frequencies <NUM>. Furthermore, the control unit <NUM> determines frequencies other than the non-recommended frequencies <NUM> included within the <NUM> frequency band, as being the recommended frequencies <NUM>. Details thereof will be described below.

In <FIG>, the X-axis indicates the frequencies, the Y-axis indicates the power levels, and the Z-axis indicates time. The time shown on the Z axis corresponds to an elapsed time from the initiation of measurement in the first instance of step S32 to the completion of measurement in the last instance of step S32. <FIG> shows only the power levels of the frequencies of the radio waves the power levels of which are greater than or equal to the power threshold value. In this example, the degree of usage of the frequency f1 is five times, the degree of usage of the frequency f2 is two times, and the degree of usage of the frequency f3 is four times. For example, in the case that three times is set as the degree threshold value, the degree of usage of the frequency f1 (five times) and the degree of usage of the frequency f3 (four times) are greater than or equal to the degree threshold value. In this case, the control unit <NUM> determines that the frequency f1 and the frequency f3 are the non-recommended frequencies <NUM>. The control unit <NUM> determines the frequencies other than the non-recommended frequencies <NUM> as being the recommended frequencies <NUM>. When step S35 is completed, the process proceeds to step S36.

In step S36, the control unit <NUM> causes the display unit <NUM> to display the non-recommended frequencies <NUM> and the recommended frequencies <NUM>. Furthermore, the control unit <NUM> causes the frequencies added with the degree of usage to be displayed. In response to a display command output from the control unit <NUM>, for example, the display unit <NUM> displays the image <NUM> shown in <FIG>. In the image <NUM> shown in <FIG>, the non-recommended frequencies <NUM> and the recommended frequencies <NUM> are displayed separately. The non-recommended frequencies <NUM> are displayed with the information "high degree of usage" added thereto. Furthermore, a portion of the recommended frequencies <NUM> (frequency f2) is displayed with the information "low degree of usage" added thereto.

The control unit <NUM> is also capable of setting, for the base wireless devices <NUM>, the recommended frequencies <NUM> as frequencies to be used. In the case of there being a plurality of the recommended frequencies <NUM>, the control unit <NUM> may set a frequency the degree of usage of which is lowest. The control unit <NUM> may also set an arbitrary frequency.

Moreover, the display system <NUM> is also capable of displaying the degree of usage in the form of a percentage. In this case, the control unit <NUM> counts, for each of the frequencies, the number of times that the power levels of the radio waves becomes greater than or equal to the power threshold value. Furthermore, in step S36, the control unit <NUM> divides the number of times counted for each of the frequencies by the total number of measurements (= Nmax). The control unit <NUM> causes the calculated values to be displayed as the degree of usage (%) on the display unit <NUM>.

According to the fourth display process, the user can be made aware of the degree of usage of the frequencies that are already being used in the industrial equipment. Further, the user is capable of setting the frequencies while avoiding those frequencies the degree of usage of which is high, from among the frequencies already being used in the industrial equipment.

The user can specify one of the base wireless devices <NUM> by operating the operation unit <NUM>. The user is capable of setting any arbitrary frequency from among the recommended frequencies <NUM> displayed on the display unit <NUM>. The control unit <NUM> transmits the frequency selected by the user to the base wireless device <NUM> that has been selected by the user. The base wireless device <NUM> carries out wireless communication using such a frequency.

Hereinafter, technical concepts which are capable of being grasped from the above-described embodiment will be described.

The first aspect of the present invention is characterized by the display system <NUM> which displays, on the display unit <NUM>, the recommended frequencies <NUM> recommended for use in the wireless device (the base wireless devices <NUM> and the remote wireless devices <NUM>) that carries out transmission and reception of data by switching between hopping frequencies in a predetermined frequency band (for example, the <NUM> frequency band), the display system comprising the measurement unit <NUM> that measures, within the set time period set in advance, the frequencies and the power levels of the radio waves propagating around the periphery of the wireless device, and the control unit <NUM> that determines the frequencies of the radio waves for which the power levels measured by the measurement unit <NUM> are less than the power threshold value set in advance, as being the recommended frequencies <NUM>, and causes the display unit <NUM> to display the recommended frequencies <NUM>.

According to the above-described configuration, frequencies that are not being used are displayed on the display unit <NUM>. Therefore, the user can easily be made aware of the free frequencies existing within a predetermined frequency band, for example, the <NUM> frequency band.

In the first aspect of the present invention, there may further be provided the operation unit <NUM> in order for the user to input the set time period.

In accordance with the above-described configuration, the user is capable of setting an appropriate set time period in accordance with the operational status of the industrial equipment. For example, in the case that wireless communications are frequently carried out in the industrial equipment, the set time period may be made shorter. In the case that wireless communications are not carried out very much, it is preferable for the set time period to be made longer.

In the first aspect of the present invention, there may further be provided the operation unit <NUM> in order for the user to input the power threshold value.

In accordance with the above-described configuration, the user is capable of appropriately setting the power threshold value in accordance with the condition of the radio waves in the industrial equipment. For example, in the case that the intensity of the radio waves is strong, the power threshold value may be made higher. In the case that the intensity of the radio waves is weak, the power threshold value may be made lower.

In the first aspect of the present invention, there may further be provided the storage unit <NUM> that stores, in advance, the plurality of occupied frequency bands that are set in the frequency band, wherein the control unit <NUM> may determine the frequencies of the radio waves having the power levels greater than or equal to the power threshold value, as being the non-recommended frequencies <NUM>, may determine all of frequencies of the occupied frequency bands including a predetermined number or more of the non-recommended frequencies <NUM>, as being the non-recommended frequencies <NUM>, and may determine frequencies that are included within the frequency band and that are other than the non-recommended frequencies <NUM> as being the recommended frequencies <NUM>.

In the case that channels of a predetermined communication standard are used, it is preferable for the control unit <NUM> to set all of the frequencies included within the occupied frequency bands of such channels as being the non-recommended frequencies <NUM>. According to the above-described configuration, in the case that a certain channel is being used, even if some of the frequencies included within the occupied frequency bands of the channel are not detected at the time of measurement, it becomes possible for all of the frequencies included within the occupied frequency bands to be determined as being the non-recommended frequencies <NUM>. Accordingly, it is possible to prevent the frequencies that are already being used from being erroneously determined as the recommended frequencies <NUM>.

In the first aspect of the present invention, the control unit <NUM> may determine the frequencies of the radio waves having the power levels greater than or equal to the power threshold value, as being the non-recommended frequencies <NUM>, and in the case that a difference between two of the non-recommended frequencies <NUM> is less than or equal to a predetermined difference, the control unit <NUM> may determine all of frequencies between the two non-recommended frequencies <NUM> as being the non-recommended frequencies <NUM>, and may determine the frequencies that are included within the frequency band and that are other than the non-recommended frequencies <NUM> as being the recommended frequencies <NUM>.

In the case that the frequencies of two of the radio waves the power levels of which are greater than or equal to the power threshold value, are in close proximity to each other, there is a possibility that the frequencies between the two frequencies are being used. According to the above-described configuration, in the case that the difference between the two of the non-recommended frequencies <NUM> is less than or equal to the predetermined difference, all of the frequencies between the two non-recommended frequencies <NUM> are determined as being the non-recommended frequencies <NUM>. Accordingly, it is possible to prevent the frequencies that are already being used from being erroneously determined as the recommended frequencies <NUM>.

In the first aspect of the present invention, the control unit <NUM> may determine the frequencies of the radio waves having the power levels greater than or equal to the power threshold value, as being the non-recommended frequencies <NUM>, may determine the frequencies that are included within the frequency band and that are other than the non-recommended frequencies <NUM> as being the recommended frequencies <NUM>, and may cause the display unit <NUM> to display the non-recommended frequencies <NUM> and the recommended frequencies <NUM> in different display forms.

In the first aspect of the present invention, the measurement unit <NUM> may periodically perform a process of measuring the frequencies and the power levels of the radio waves within the set time period, and the control unit <NUM> may cause the display unit <NUM> to display the degree of usage of the frequencies of the radio waves having the power levels greater than or equal to the power threshold value.

In accordance with the above-described configuration, the user can be made aware of the degree of usage of the frequencies that are already being used.

In the first aspect of the present invention, there may further be provided the operation unit <NUM> in order for the user to input the degree threshold value of the non-recommended frequencies, wherein the measurement unit <NUM> may periodically perform a process of measuring the frequencies and the power levels of the radio waves within the set time period, and the control unit <NUM> may determine, from among the frequencies of the radio waves having the power levels greater than or equal to the power threshold value, frequencies with a degree of usage greater than or equal to the degree threshold value as being the non-recommended frequencies <NUM>, and may determine the frequencies that are included within the frequency band and that are other than the non-recommended frequencies <NUM> as being the recommended frequencies <NUM>.

In accordance with the above-described configuration, from among the frequencies already being used, the user is capable of setting the frequencies while avoiding those frequencies the degree of usage of which is high.

In the first aspect of the present invention, the control unit <NUM> may set, for the wireless device (the base wireless devices <NUM>), the recommended frequencies <NUM> as frequencies to be used.

The second aspect of the present invention is characterized by the display system <NUM> which displays, on the display unit <NUM>, the non-recommended frequencies <NUM> not recommended for use in the wireless device (the base wireless devices <NUM> and the remote wireless devices <NUM>) that carries out transmission and reception of data by switching between hopping frequencies in a predetermined frequency band (for example, the <NUM> frequency band), the display system comprising the measurement unit <NUM> that measures, within the set time period set in advance, the frequencies and the power levels of the radio waves propagating around the periphery of the wireless device, and the control unit <NUM> that determines the frequencies of the radio waves for which the power levels measured by the measurement unit <NUM> are greater than or equal to the power threshold value set in advance, as being the non-recommended frequencies <NUM>, and causes the display unit <NUM> to display the non-recommended frequencies <NUM>.

Claim 1:
A display system (<NUM>) configured to display, on a display unit (<NUM>), recommended frequencies (<NUM>) recommended for use in a wireless device (<NUM>, <NUM>) configured to carry out transmission and reception of data by switching between hopping frequencies in a predetermined frequency band, the display system comprising:
a measurement unit (<NUM>) configured to periodically measure, within a set time period set in advance, frequencies and power levels of radio waves propagating around the wireless device; and
a control unit (<NUM>) configured to determine, from among frequencies of the radio waves for which the power levels measured by the measurement unit are greater than or equal to a power threshold value set in advance, frequencies with a number of times of being used greater than or equal to a predetermined number of times, or frequencies with a percentage calculated by dividing the number of times of being used by a number of measurement by the measurement unit greater than or equal to a predetermined threshold, as being the non-recommended frequencies (<NUM>), to determine frequencies that are included within the frequency band and that are other than the non-recommended frequencies (<NUM>) as being the recommended frequencies (<NUM>), and to cause the display unit to display the recommended frequencies.