MX2014008321A

MX2014008321A - Method and apparatus for protecting a miner.

Info

Publication number: MX2014008321A
Application number: MX2014008321A
Authority: MX
Inventors: Michael W Bertosh; Michael Berube; Kelly Norton; Brian Dunkin
Original assignee: Strata Products Worldwide Llc
Priority date: 2013-07-18
Filing date: 2014-07-07
Publication date: 2015-05-27
Also published as: CN104481589A; MX352765B; ZA201405172B; GB2516563A; GB201412173D0; CA2856941A1; AU2014203749A1; CL2014001869A1; CA2856941C; RU2014129585A; AU2014203749B2; PL408900A1

Abstract

An apparatus for protecting a miner from injury by a machine in a mine includes an explosion-proof housing. The apparatus includes a proximity sensing portion disposed in the explosion-proof housing having a magnetic field source which produces a magnetic field that is used to sense a location of the miner relative to the machine. The apparatus includes a wireless communication portion disposed in the explosion-proof housing through which the magnetic field produced by the magnetic field source is changed remotely and wirelessly from outside the explosion-proof housing. A method for protecting a miner from injury by a machine. A system for protecting a miner from injury by a machine in a mine.

Description

METHOD AND APPARATUS TO PROTECT A MINER Field of the Invention The present application is related to a proximity detection portion which can be controlled remotely through a telecommunications network. More specifically, the present invention relates to a proximity detection portion that can be controlled remotely through a telecommunications network, such as i-Fi, to change the magnetic fields or to reprogram the proximity detection portion.

Background of the Invention The proximity detection portions found in mines have an explosion-proof housing that protects them from damage. To be able to access the components of the proximity detection portion to, for example, reprogram the microprocessors within the proximity detection portion or change the magnetic field sizes produced by the proximity detection portion with a potentiometer, the housing Explosion-proof has to be open. Opening the explosion-proof housing is a tedious, labor-intensive and time-consuming task that can easily require that 30 or more screws be removed, and subsequently return to Ref.:Z49590 its place when the explosion-proof housing is closed. The present invention eliminates the need to have to open the explosion-proof housing to access the proximity detection portion for common functions such as data collection, changing the magnetic field sizes and reprogramming the microcomputers in the detection portion of proximity; and even allowing these operations to be carried out remotely from the proximity detection portion.

Brief Description of the Invention The present invention relates to an apparatus for protecting a miner from injuries by a machine. The apparatus comprises an explosion-proof housing. The apparatus comprises a proximity detection portion disposed in the explosion-proof housing having a magnetic field source which produces a magnetic field which is used to detect a miner's location relative to the machine. The apparatus comprises a wireless communication portion disposed in the explosion-proof housing through which the magnetic field produced by the magnetic field source is remotely and wirelessly changed from outside the explosion-proof housing. The wireless communication portion is in electrical communication with the proximity detection portion.

The present invention relates to a method for protecting a miner from injuries by a machine. The method comprises the steps of placing a proximity detection portion with the machine. There is the step of moving the machine in the mine. It is the step of remotely changing wirelessly from outside an explosion-proof housing of the proximity detection portion through a wireless communication portion disposed in the explosion-proof housing, a magnetic field produced by a field source magnetic field of a proximity detection portion disposed in the explosion-proof housing of the proximity detection portion, the magnetic field is used to detect a location of the miner relative to the machine, the wireless communication portion in electrical communication with the Proximity detection portion.

The present invention relates to a system for protecting a miner from injury, as shown in Figure 6. The system comprises an apparatus having a proximity detection portion that can have its magnetic field remotely changed by means of a network of telecommunications. The apparatus was described above. The system comprises a machine with the apparatus. The system includes a personal alarm device used by the miner to alert the miner when the miner is inside a predetermined distance, ie from 0.60 meters to 3.0 meters from the machine (2 to 10 feet). The system comprises a wireless communication network in communication with the wireless communication portion. The system comprises a remote controller from the apparatus in communication with the network through which the controller communicates remotely and wirelessly with the apparatus to change the magnetic field produced by the magnetic field source. The controller has a wireless communication portion such as a wired module.

Brief Description of the Figures Figure 1 is a block diagram of an apparatus of the present invention.

Figure 2 is a representation of the apparatus.

Figure 3 is a computer generated image of the apparatus.

Figure 4 is a representation of a PAD.

Figure 5 is a representation of the apparatus on a machine.

Figure 6 is a block diagram of a system of the present invention.

Detailed description of the invention Referring now to the figures in which the reference numbers refer to identical or similar parts through various views, and more specifically to Figures 1, 2 and 5 thereof, an apparatus is shown 10 to protect a miner from injuries by a machine 12.

The apparatus 10 comprises an explosion-proof housing 14. The apparatus 10 comprises a proximity detection portion 16 disposed in the explosion-proof housing 14 having a magnetic field source 20 which produces a magnetic field which is used for detecting a location of the miner relative to the machine 12. The apparatus 10 comprises a wireless communication portion 22 disposed in the explosion-proof housing 14 through which the magnetic field produced by the magnetic field source 20 is remotely changed and wirelessly from outside the explosion-proof housing 14. The wireless communication portion 22 is in electrical communication with the proximity detection portion 16. The screws 19 hold the housing 18 sealed and closed.

The proximity detection portion 16 may include at least a first microprocessor 24, and the first microprocessor 24 is reprogrammed remotely and wirelessly from outside the explosion-proof housing 14 through the wireless communication portion 22. The communication portion wireless 22 may include a receiver 26 through which signals to change the magnetic field are received wirelessly. The wireless communication portion 22 may include a transmitter 28 from which the signals of transmission are sent wirelessly from the explosion-proof housing 14.

The wireless communication portion 22 may include a Wi-Fi module 30 having the transmitter 28 and the receiver 26. The wireless communication portion 22 may include a Wi-Fi microprocessor 32 in electrical communication with the Wi-Fi 30 module. wireless communication portion 22 may include a real-time clock 34 in electrical communication with the Wi-Fi microprocessor 32 which provides a time marker for the data received by the Wi-Fi microprocessor 32 and stored in a memory 36 of the Wi microprocessor -Fi 32. The wireless communication portion 22 may include an antenna 38, and the explosion-proof housing 14 includes a cable gland 40 through which the antenna 38 extends from the explosion-proof housing 14. The portion of wireless communication 22 may include a cable port 42 through which the Wi-Fi module 30 is reprogrammed when the Wi-Fi 30 module is not working properly. just. An example of a Wi-Fi system of a mine is described in the US patent application No. 14 / 290,755, incorporated herein by reference. An example of the safety system for a mining equipment is based on the proximity detection portion 16 described in United States Patent 7,420,471 incorporated herein by reference.

The present invention relates to a method for protecting a miner from injuries by a machine 12. The method comprises the steps of placing a proximity detection portion 16 with the machine 12. There is the step of moving the machine 12 in the mine . There is the step of remotely changing wirelessly from outside the explosion-proof housing 14 through a wireless communication portion 22 disposed in the explosion-proof housing 14, a magnetic field produced by a magnetic field source 20 of the portion Proximity detection device 16 arranged in the explosion-proof housing 14 of the proximity detection portion 16. The magnetic field is used to detect a location of the miner relative to the machine 12. The wireless communication portion 22 in electrical communication with the proximity detection portion 16.

There may be the step of reprogramming a first microprocessor 24 of the proximity detection portion 16 remotely and wirelessly from outside the explosion-proof housing 14 through the wireless communication portion 22. There may be the step of receiving wirelessly through a receiver 26 of the wireless communication portion 22 signals to change the magnetic field. There may be the step of transmitting wirelessly from the explosion-proof housing 14 with a transmitter 28 of the wireless communication portion 22 of the housing 14, transmission signals. The wireless communication portion 22 may include a Wi-Fi module 30 having the transmitter 28 and the receiver 26.

The wireless communication portion 22 may include a Wi-Fi microprocessor 32 in electrical communication with the Wi-Fi module 30. The wireless communication portion 22 may include a real-time clock 34 in electrical communication with the Wi-Fi 32 microprocessor, and there may be the step of providing a time marker for data received by the Wi-Fi microprocessor 32 and stored in a memory 36 of the Wi-Fi microprocessor 32. The wireless communication portion 22 may include an antenna 38, and the housing a Explosion test 14 may include a cable gland 40 through which the antenna 38 extends from the explosion-proof housing 14. The wireless communication portion 22 may include a cable port 42, and there may be the step of reprogramming the Wi-Fi module 30 through the cable port 42 when the Wi-Fi 30 module is not working properly.

In the operation of the invention, an apparatus 10 having a proximity detection portion 16 with Wi-Fi capability is capable of transmitting data as well as receiving signals to reprogram and change the field sizes of the proximity detection portion 16. With reference to figure 1, a antenna 38 extends from the explosion-proof housing 14 of the proximity detection portion 16 through an MSHA-approved cable gland 40 that protects the components within the explosion-proof housing 14 of the mine environment. The antenna 38 extends from the explosion-proof housing 14 and is electrically connected to a Wi-Fi module 30 disposed within the explosion-proof housing 14. The Wi-Fi module 30 is, for example, miniWi-Fi 01 or part number 1W-SM2128M1-C available for purchase at ConnectionOne in San Jose, California. This Wi-Fi module 30 has the functionality of receiver and transmitter necessary to support the operation described herein.

The data from the data microprocessor 48 in the explosion-proof housing 14 is sent to an interface, a header J7 of the proximity detection portion 16. From the header J7, the data is sent to a location where the signals of voltage are converted, an RS485 / TTL which is connected to the J7 header through a serial connection, an RS485 connection. The data is then sent from the RS485 / TTL over a serial connection, a universally asynchronous receiver / transmitter connection (UAR.T, to its acronym in English) to a Wi-Fi microprocessor 32 that receives the data and stores the data in a memory 36. The memory 36 in the Wi-Fi 32 microprocessor can store the data for a month if desired. The data that is stored in the memory 36 of the Wi-Fi microprocessor is also provided with a time marker. The time marker is obtained by the Wi-Fi microprocessor 32 which requests a time marker from a real time clock 34 over an SPI connection through which the Wi-Fi microprocessor 32 is connected to the real time clock 34. A battery 46 dedicated to the real-time clock 34 is connected to the real-time clock 34 to support the real-time clock 34 as necessary. This battery 46 can last for many years. The data stamped over time is provided from the Wi-Fi microprocessor 32 to the Wi-Fi module 30 through a UART connection. The data with time marker are then transmitted from the Wi-Fi module 30 and outside the explosion-proof housing 14 through the antenna 38.

To reprogram the field sizes of the proximity detection portion 16, the reprogramming signals are received by the antenna 38 and provided to the Wi-Fi module 30. From the Wi-Fi module 30 through the UART connection, the signals are provided to the Wi-Fi microprocessor 32. From the Wi-Fi microprocessor 32, the reprogramming signals are provided to an interface, a J5 header through a programming line, an ICSP connection. From the J5 header, the signals from reprogramming are provided to the data microprocessor 48. The data microprocessor 48 recognizes the reprogramming signals and provides those reprogramming signals via an SPI connection to a master microprocessor 50 of the proximity detection portion 16. The reprogramming signals provided to the master microprocessor 50 from the data microprocessor 48 are the same as those that existed in standard proximity detection portions. The reprogramming signals from the data microprocessor 48 are basically the same signals that would be provided to the master microprocessor 50 if a potentiometer were used, as was common in the past, to change the field sizes. In a preferred embodiment, the Wi-Fi controller board 72 described herein is disposed in and connected to the proximity controller board 66 of the HazardAvert proximity module, incorporated herein by reference, sold by Strata Safety Products, Sandy Springs, Georgia. This module is waterproof, shielded and explosion proof.

The pulse / echo microprocessor 52, the master microprocessor 50, the data microprocessor 48 and the headers J8, J5 and J7 (interfaces) are part of an existing proximity detection portion controller board 66 that already exists in portions of proximity detection 16. The Wi-Fi capability is essentially matched to communicate with the existing proximity controller board 66 so that minimal changes are made to the proximity controller board 66 and the components thereof. The changes are software or functional in nature to the proximity controller board 66 to allow the data microprocessor 48 to recognize the signals that are received from the Wi-Fi module 30, or that are sent to the Wi-Fi module 30. The Wi capacity -Fi provided by the components of the Wi-Fi controller board 72 essentially mimic the signals that exist in those of proximity detection portions 16 of the prior art which used manual connectivity to receive signals from or provide signals to the proximity controller board 66 after that the explosion-proof housing 14 was open.

If there is a problem with the Wi-Fi 30 module, access to the Wi-Fi 30 module for diagnostic or reprogramming purposes is obtained through a location where voltage signals are converted, an RS232 / TTL from a serial connection , an RS232 line. The RS232 / TTL is accessed by opening the explosion-proof housing 14 as it has been done in the past to change the field sizes. The Wi-Fi 30 module, the real-time clock 34, the battery 46, RS485 / TTL and RS232 / TTL are all part of the Wi-Fi controller board 72 that is inserted into the housingExplosion-proof 14 and connected with the 66 proximity controller board.

Each of the microprocessors of the proximity controller board 66 is capable of being reprogrammed via Wi-Fi. The pulse / echo microprocessor 52 has a bi-directional ICSP connection with the J8 header and the J8 header has a bidirectional ICSP connection with the Wi-Fi 32 microprocessor. The master microprocessor and the data microprocessor of the proximity control board 66 have each one a bidirectional ICSP connection with the J5 header, and the J5 header has a bidirectional ICSP connection with the Wi-Fi 32 microprocessor. As mentioned earlier, the Wi-Fi 32 microprocessor has a bidirectional UART connection with the Wi-Fi module that it is in communication through antenna 38 with the outside world to receive and send wireless signals.

When any or each of the microprocessors in the proximity control board 66 wish to reprogram, the code is received by the antenna 38 and provided to the Wi-Fi module 30 and then to the Wi-Fi 32 microprocessor. If the code is for reprogramming the pulse / echo microprocessor 52, the code is provided through the header J8 to the pulse / echo microprocessor 52. If the code is for reprogramming the master microprocessor 50 or the data microprocessor 48, the code is provided from the Wi-Fi 32 microprocessor to the J5 header and then to either the master microprocessor or the data microprocessor. The connections are bidirectional such that all the code in each of the microprocessors in the proximity controller board 66 are capable of being reviewed and read, as desired and as needed, wirelessly from a remote location through the Wi-module. -Fi. 1. How the magnetic fields are changed: There are two methods: A. Magnetic fields changed through connector connection.

Using software written for this purpose, the user connects to the Wi-Fi proximity module 30 using either an infrastructure Wi-Fi network connection or an ad hoc Wi-Fi network connection. The ad hoc mode is used when the connection is point-to-point between the PC running the software and the same device 10. The infrastructure mode is used when the Wi-Fi 72 board has been established over an existing Wi-Fi network . Once the connection is made, the program establishes a connector connection with the Wi-Fi proximity module 30. The user of the software can then consult or set the values of the magnetic field as a percentage. To establish a field, the software sends a special command about this connection of the connector to the Wi-Fi module 30. The Wi-Fi 32 microprocessor on the Wi-Fi board 72 periodically queries a parameter change flag in the Wi-Fi module 30. When you see that this value has changed, it then asks to the Wi-Fi module 30 for all possible parameter changes. (All field settings, code load, etc.). The Wi-Fi microprocessor 32 takes the new field value and then converts it from a percentage to the actual value used by the data microprocessor 48. The Wi-Fi microprocessor 32 then places the data microprocessor 48 in programming mode, reads the field values that have already been stored in the EEPROM of the data microprocessor and update those values with the new settings. The Wi-Fi 32 microprocessor also sets a flag of "new field values" in the EEPROM of the data microprocessor that the microprocessor checks when it boots. The Wi-Fi microprocessor 32 releases the data microprocessor 48 from the programming mode. Once the data microprocessor 48 has been released from the programming mode, it restarts. When starting, it checks its EEPROM by the "new field values" flag. Upon seeing that the flag is set, it sends the new field value indicated by the flag to the master microprocessor 50 to let the master microprocessor know that there is a new field generator value for a particular generator from the source 20. The master microprocessor 50 then performs a voltage calibration for that generator. For this moment, the generator field value has been changed.

B. Magnetic fields changed through web page parameters.

This works in the same way as above, except that the field value is changed from a web page that can be accessed from any network enabled device (i-Phone, PC, etc.). The value is changed by means of accessing the web page hosted by the network server of the Wi-Fi board of the Wi-Fi 30 module. 2. How to load new firmware The code load is initiated by means of a special PC code loading software. By using software written for this purpose, the user connects to the Wi-Fi proximity module 30 using either an infrastructure Wi-Fi network connection or an ad hoc connection. The ad hoc mode is used when the connection is point-to-point between the PC running the software and the same device 10. The infrastructure mode is used when the Wi-Fi 72 board has been established over an existing Wi-Fi network . Once the connection is made, the program establishes a connector connection with the Wi-Fi proximity module 30. The PC program sends a command to the Wi-Fi 30 module to let the Wi-Fi 32 microprocessor know that a session of programming is requested. This command contains information that tells which microprocessor to program (data, master or p / e) and the size of the new image. If the size is within the appropriate limits, the Wi-Fi 32 microprocessor recognizes the request. The PC program then sends the image to be programmed in a standard Intel hex file format. The Wi-Fi microprocessor 32 receives this new image and saves it to the internal flash memory 36. (This means that the Wi-Fi microprocessor 32 will have a copy of the image in its memory 36 even through power cycles; Wi-Fi 32 microprocessor could be reprogrammed at a future point without having a new image sent via Wi-Fi). The Wi-Fi microprocessor 32 converts this hex file stored in the flash memory 36 to three binary images in RAM that coincide with the three memory spaces of the Wi-Fi microprocessor (flash, EEPROM and bytes config). The Wi-Fi microprocessor 32 sets the processor to be programmed from the proximity detection portion 16 in programming mode by means of establishing the high MCLR line (12v). Each memory area 36 is programmed through ICSP (In Circuit Serial Programing). Once a memory area 36 has been programmed, it is read back and compared with the image in the RAM to verify that the programming was successful. While this is happening the Wi-Fi 32 microprocessor is sending messages back to the PC indicating the status and current status of the programming session. Once the programming has been completed, the Wi-Fi 30 module will send a message back to the PC indicating success and then close the connector connection.

Examples of mining equipment on which the proximity detection portion 16 is used are the following: Continuous mining Transport car_ Transport system_ Roof mining Cargo-transport-desec Cintra transportadora_ Wheelbarrow_ Extreme end charger Transport truck_ The proximity detection system for the mining industry works by establishing a magnetic marker field - or area around the machinery that uses the proximity detection portion 16, also known as the generator (or proximity module depending on the type). of mining). One or more of the devices 10 can be adjusted on machinery to create fields designated as the "WARNING AREA" and "DANGER ZONE". This marker field can encompass the entire machine 12 and its turning radius, or it can be specific for certain areas.

The miners use a personal alarm device (PAD) 44 as shown in figure 4, which detects and measures the magnetic marker field to determine its proximity to the machine 12, and alert them to possible danger to your safety. The PAD 44 is attached to the miners' belts and has an optional "warning module" clip that attaches to the helmet.

Visible and audible alarms for the miner and operator of the machine 12 While the miner enters the warning zone around the machinery, visual and audible alarms alert both the miner and the operator of the machine 12. If the miner enters the danger zone, a product, such as Hazard Avert sold by Strata Worldwide LLC of Georgia, can be programmed to turn off machine 12 completely.

The present invention relates to a system 60 for protecting a miner from injury, as shown in Figure 6. The system 60 comprises an apparatus 10 having a proximity detection portion 16 which may have its magnetic field remotely changed to through a telecommunications network 74. The apparatus 10 was described previously. The system comprises a machine 12 with the apparatus 10. The system comprises a personal alarm device 44 used by the miner to alert the miner when the miner is within a predetermined distance ie between 0.6 meters and 3.04 meters from the machine 12. The system 60 comprises a wireless communication network 74 in communication with the wireless communication portion 16. The system 60 comprises a remote controller 80 of the apparatus 10 in communication with the network 74 through which the controller 80 communicates remotely and wirelessly with the apparatus 10 for changing the magnetic field produced by the magnetic field source 20. The controller has a wireless communication portion, such as a wired module.

Figures 2 and 3 show the apparatus 10 with a proximity detection portion 16, otherwise known as a field generator, for surface mining and hard rock. Figure 5 shows a field generator for coal mining on a machine 12. Figure 4 shows a PAD 44 approved by MSHA for coal mining.

Although the invention has been described in detail in the foregoing embodiments for illustrative purposes, it should be understood that such detail is only for that purpose and that variations may be made by experts in the art without departing from the spirit and scope of the invention except as can be described in the following claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. An apparatus for protecting a miner from injuries by a machine in a mine, characterized in that it comprises: an explosion-proof housing; a proximity detection portion disposed in the explosion-proof housing having a magnetic field source which produces a magnetic field that is used to detect a miner's location relative to the machine, - a wireless communication portion disposed in the Explosion-proof housing through which the magnetic field produced by the magnetic field source is remotely and wirelessly changed from outside the explosion-proof housing, the wireless communication portion in electrical communication with the proximity detection portion.

2. The apparatus according to claim 1, characterized in that the proximity detection portion includes at least a first microprocessor, and the first microprocessor is reprogrammed remotely and wirelessly from outside the explosion-proof housing through the communication portion. Wireless

3. The apparatus according to claim 2, characterized in that the wireless communication portion includes a receiver through which the signals to change the magnetic field are received wirelessly.

4. The apparatus according to claim 3, characterized in that the wireless communication portion includes a transmitter from which the transmission signals are sent wirelessly from the explosion-proof housing.

5. The apparatus according to claim 4, characterized in that the wireless communication portion includes a Wi-Fi module having the transmitter and the receiver.

6. The apparatus according to claim 5, characterized in that the wireless communication portion includes a Wi-Fi microprocessor in electrical communication with the Wi-Fi module.

7. The apparatus according to claim 6, characterized in that the wireless communication portion includes a real-time clock in electrical communication with the Wi-Fi microprocessor which provides a time marker for the data received by the Wi-Fi microprocessor and stored in a Wi-Fi microprocessor memory.

8. The apparatus according to claim 7, characterized in that the wireless communication portion includes an antenna and the explosion-proof housing includes a cable gland through which the antenna extends from the explosion-proof housing.

9. The apparatus according to claim 8, characterized in that the wireless communication portion includes a cable port through which the Wi-Fi module is reprogrammed when the Wi-Fi module is not working properly.

10. A method to protect a miner from injuries by a machine in a mine, characterized in that it comprises the steps of: placing a proximity detection portion disposed in an explosion-proof housing with the machine; move the machine in the mine; Y remotely and wirelessly changing from outside the explosion-proof housing through a wireless communication portion disposed in the explosion-proof housing a magnetic field produced by a magnetic field source of the proximity detection portion disposed in the housing to Explosion test, the magnetic field is used to detect a miner's location relative to the machine, the wireless communication portion in electrical communication with the proximity detection portion.

11. The method according to claim 10, characterized in that it includes the step of reprogramming a first microprocessor of the proximity detection portion remotely and wirelessly from outside the explosion-proof housing through the wireless communication portion.

12. The method according to claim 11, characterized in that it includes the step of wirelessly receiving signals to change the magnetic field through a receiver of the wireless communication portion.

13. The method according to claim 12, characterized in that it includes the step of transmitting wirelessly from the explosion-proof housing with a transmitter of the wireless communication portion that hosts the transmission signals.

14. The method according to claim 13, characterized in that the wireless communication portion includes a Wi-Fi module having the transmitter and the receiver.

15. The method according to claim 14, characterized in that the wireless communication portion includes a Wi-Fi microprocessor in electrical communication with the Wi-Fi module.

16. The method according to claim 15, characterized in that the wireless communication portion includes a real-time clock in electrical communication with the Wi-Fi microprocessor, and includes the step of providing a time marker for the data received by the Wi-Fi microprocessor and stored in a microprocessor memory Wifi.

17. The method according to claim 16, characterized in that the wireless communication portion includes an antenna and the explosion-proof housing includes a cable gland through which the antenna extends from the explosion-proof housing.

18. The method according to claim 17, characterized in that the wireless communication portion includes a cable port, and includes the step of reprogramming the Wi-Fi module through the cable port when the Wi-Fi module is not working properly.

19. A system to protect a miner from injuries by a machine in a mine, characterized in that it comprises: an apparatus that has an explosion-proof housing; a proximity detection portion disposed in the explosion-proof housing having a magnetic field source which produces a magnetic field that is used to detect a mining location relative to the machine; a portion of wireless communication arranged in the Explosion-proof housing through which the magnetic field produced by the magnetic field source is remotely and wirelessly changed from outside the explosion-proof housing, the wireless communication portion in electrical communication with the proximity sensing portion disposed on the machine in a personal alarm device arranged on the miner; a wireless communication network in communication with the wireless communication portion; Y a remote controller of the apparatus in communication with the network through which the controller communicates remotely and wirelessly with the apparatus to change the magnetic field produced by the magnetic field source.