DE3877488T2 - DETECTION SYSTEM FOR OBJECTS. - Google Patents

Description

The present invention relates to an object recognition system used for automatically handling and exchanging tools of a machine tool, handling parts and products in a factory, recognizing objects in a real distribution network, and the like.

Description of the state of the art

In order to convert the automatic exchange or handling of tools of a machine tool, the discrimination of parts and products on an assembly line in a factory or the like to machine operation, a system for recognizing and controlling the objects such as tools, parts, products and the like is generally necessary. In order to meet this requirement, an object recognition system has recently been developed. This system comprises a write/read control unit and a head connected thereto. The write/read control unit is connected to a main (superordinate or host) control device including a computer system. On the other hand, an identification unit including a non-volatile memory is provided to to store identification data or the like of an object, attached to the objects fed to, for example, an assembly line. When an object reaches the location of the head, data is written into or read from the identification unit by means of the head in a non-contact manner under the control of the write/read control unit in response to a command from the main control device.

Since data transmission/reception is carried out between the head of the read/write control unit and the identification unit in a non-contact manner, if the distance between the head and the identification unit is inappropriate, a situation may arise that data cannot be reliably written or read out. Therefore, after installation, adjustment of the distance between the head and the identification unit and positioning thereof become important and difficult adjustment work is required. On the other hand, after position adjustment has been carried out once, there is a case where the distance at which data can be reliably written or read out changes due to noise, accompanying circumstances or the like, so that readjustment is required.

However, the conventional object detection system does not have a stable operation indicator to indicate that the data writing/reading operations can be performed correctly. Therefore, it is difficult to confirm the writing/reading operation range with certainty. Furthermore, since the writing/reading operations for the detection unit are performed in response to a command from the main controller, the worker must go to the place where the main controller is installed after adjustment in a work area where the head is installed and check the data written/reading operations from the main controller. working area to operate the main control device. Therefore, problems arise such that the adjustment work is difficult and time-consuming. Furthermore, the write/read data cannot be checked or corrected in the working area where the head is located.

In the object detection system, a plurality of read/write control units to be installed in the work area are generally connected to a main control device.

The main control device is connected to a plurality of control units via transmission lines and issues write/read commands and the like together with the assigned unit number to each of the write/read control units. When the command issued from the main control device includes its own number, the write/read control unit recognizes this command and carries out transmission/reception of the data to/from the identification unit in accordance with this command.

After the completion of the read/write operations, the read/write control unit returns a response indicating that the command was correctly executed to the main controller along with its own number. In contrast, if the command could not be completed correctly, the read/write control unit returns an error code response indicating the type of error that occurred to the main controller along with its own number. When the error code responses are returned, the main controller stores the error code data of each read/write control unit and manages the errors.

In such a conventional system, the generated error data is managed as a whole by the main control device. Therefore, when a large number of writing /Read control units connected to the main control device, a problem arises such that the load on the main control device for managing the generated errors increases.

DESCRIPTION OF THE INVENTION

The present invention has been made in view of the above problem, and it is an object of the invention to propose an object recognition system for writing/reading data based on commands from a main (host) control device, in which the writing/reading operations for an identification unit can also be performed based on commands from writing/reading control units.

Another object of the invention is to provide an object recognition system for writing/reading data based on commands from a main control device, in which the write/read operations for an identification unit can also be carried out based on commands from the write/read control units and can also be carried out continuously in a predetermined operating mode.

Still another object of the invention is to provide an object detection system in which the load on a main control device is reduced and error data can also be monitored by each read/write control unit when necessary.

According to the present invention, an object recognition system is provided which comprises a head for performing data transmission or reception in a contactless manner for an identification unit storing identification data of an object and a write/read control unit for controlling the data transmission or reception via the head in accordance with the commands from a main control device, the write/read control unit being provided with a monitor unit having mode setting means for selecting either the first or second mode, key input means for inputting the commands relating to data transmission or reception for the identification unit, and display means. When the first mode is selected, the write/read control unit is made operative based on the command from the main control device, and when the second mode is selected, the write/read control unit is made operative based on the key input from the monitor unit.

In this object recognition system, when the second mode is selected via the mode setting device in the monitor unit, a write or read command is input to the read/write control unit by operating the key input device in the monitor unit. Therefore, data is written to or read from the identification unit and the result is displayed on the display device in the monitor unit.

According to the invention, the monitor unit, which has the mode setting means for selecting either the first mode (RUN mode) or the second mode (MONITOR mode), the key input means for inputting commands related to data transmission or reception for the identification unit, and the display means, is provided for the write/read control unit. Therefore, even if the write/read control unit is separated from the main control device, the write/read control unit can write or read data into or from the identification unit. In the working field in which the head and the write/read Control unit and which is away from the main controller, adjustment of the distance between the head and an object and checking of the write/read data can be easily performed.

According to the invention, there is provided an object recognition system comprising a head for performing data transmission or reception in a non-contact manner for an identification unit storing identification data of an object, and a write/read control unit for controlling data transmission or reception via the head in accordance with commands from a main control device, the write/read control unit being equipped with a monitor unit having means for determining a test mode, key input means for entering commands relating to data transmission or reception for the identification unit, and display means, the write/read control unit comprising means for receiving a key input signal from the monitor unit, means for continuously performing the write/read operations for the identification unit in response to the determination of the test mode, and means to distinguish whether each of the write/read operations has been performed correctly or not, and to display the discrimination result on the display device of the monitor unit.

In this object detection system, when the test mode is determined in the monitor unit, the writing and reading operations are then carried out continuously. A check is made to see whether each of the writing/reading operations has been carried out correctly or not, and the result is displayed on the display unit of the monitor unit. Therefore, it is possible to check whether or not each of the read/write operations has been performed correctly at each distance in the test mode provided while the identification unit is being moved toward or away from the head, that is, while adjusting the distance between the identification unit and the head. The distance from the identification unit to the head can be easily adjusted, thereby allowing the identification unit to be set at the appropriate distance.

According to the invention, there is provided an object recognition system comprising a head for performing data transmission/reception in a non-contact manner for an identification unit storing identification data of an object, and a write/read control unit for controlling data transmission/reception through the head in accordance with commands from a main control device, the write/read control unit comprising means for discriminating whether or not errors have occurred in data transmission/reception, and error data storage means for sequentially storing the errors of each kind discriminated by the discriminating means. Preferably, the write/read control unit comprises monitor means for outputting the error data when necessary.

In this object detection system, when a command is input from the main control device, the write/read operation is carried out according to the command. The occurrence of errors is discriminated at each end of the write/read operation. When errors occur, they are stored in the error data storage device in sequence, each type of error. This error data is displayed and output by the monitor device when necessary. Therefore, even if the main control device manages a plurality of write/read control units, the error management is performed by each write/read control unit, so that the load on the main control device is reduced. When a plurality of write/read control units are connected to the main control device, the information indicating in which unit in the system and what type an error occurs can be obtained by monitoring the contents stored in the storage device of each unit, so that the maintenance of the system can be easily performed. On the other hand, the cause and frequency of the errors occurred can be monitored in the work field in which the unit is installed, and a countermeasure can be taken.

Fig. 1 is a block diagram showing a schematic structure of an object recognition system in an embodiment of the present invention;

Fig. 2 is a schematic drawing illustrating an operation panel of a monitor unit in the object detection system;

Fig. 3 is a schematic drawing for explaining the attachment of the monitor unit to a read/write control unit;

Fig. 4 is an enlarged schematic drawing of the control panel of the monitor unit;

Fig. 5 is a block diagram showing a circuit arrangement of the write/read control unit and the monitor unit;

Figs. 6 and 7 are flow charts for explaining the operation of the object recognition system;

Fig. 8 is a flow chart for explaining the operation of the object recognition system in another embodiment; and

Fig. 9 is a flow chart for explaining the operation of an object recognition system in another embodiment.

Fig. 1 is a block diagram showing a schematic arrangement of an object recognition system in an embodiment of the present invention.

In the object recognition system of this embodiment, a write/read control unit 4 writes or reads data into or from an identification unit 2 attached to an object 1 via a head 5 through the electromagnetic coupling in response to commands from a main (host) control device 6 including a computer and the like. In this system, a monitor unit 7 is attached to the write/read control unit 4. The monitor unit 7 can select either a RUN mode or a MONITOR mode as explained below. When the RUN mode is selected, the write/read control unit 4 executes the write/read operation of the identification data or the like for the identification unit 2 in accordance with a command from the main control device 6. On the other hand, when the MONITOR mode is selected, the main control device 6 is electrically separated from the write/read control unit 4, and the write/read control unit 4 performs the control of the write/read operation or the like of the identification data or the like for the Identification unit 2 in response to a command from the monitoring unit 7.

Fig. 2 shows a control panel 7a of the monitor unit 7. On the control panel 7a, a display unit 11, an operating mode setting device 12 for switching between the RUN mode and the MONITOR mode and a group of buttons 13 are provided. To explain these keys, Fig. 4 shows an enlarged diagram of the control panel 7a. In addition to a test key 31, a reset key 32 and an error key 33, the key group 13 includes the following keys as typical keys: a read key 41, write keys 42, a clear key 43, a key 44 with an arrow in the left direction, a key 45 with an arrow in the right direction, a decrease or step-decrease (ABN) key 46, a step-increase (ZUN) key 47, a set key 48 and the like. These function keys are usually used as keys for inputting letters, e.g. A, B, C, etc., or digits from 0 to 9. Switching between the function keys and the alphabet/digit keys is performed by using a predetermined key (e.g., the C key).

As shown in Fig. 3, the monitor unit 7 has a connector 14 on the lower side. The monitor unit 7 is mounted on the write/read control unit 4 such that the connector 14 is fitted into a connector 15 formed on the upper side of the write/read control unit 4 and is electrically connected to the connector 15. The control unit 4 further has a connector 16 for connecting to the head 5 and a connector 17 for connecting to the main controller 6. A light emitting diode (LED) 25 for indicating errors is attached to the upper surface of the write/read control unit 4.

Fig. 5 shows a circuit diagram of the write/read control unit 4 and the monitor unit 7. The control unit 4 has: an interface 18 to the main control device 6; an MPU (microprocessor unit) 19; a RAM 20; a transmission/reception interface 21 for the identification unit; and an external interface 22 for connecting to the monitor unit 7.

The monitor unit 7 comprises: key switches SW1 to SW16, which are turned on by depressing the keys of the key group 13; the liquid crystal display device (LCD) 11; the mode setting device (switch) 12; an LCD display driver 23; and an expansion port 24.

The operation of the object recognition system of the embodiment will now be described with reference to the flow charts shown in Figs. 6 and 7. The operations in these flow charts are executed under the control of the MPU 19.

When a power source is turned on and the operation is started, initialization is first carried out (step 1 (hereinafter referred to as ST 1)). Next, a test is made to see whether the operation mode is in the MONITOR mode or not (ST 2). Assuming that the operation mode setting means 12 is set to the RUN mode and that the read/write control unit 4 is connected to the main controller 6, the answer at ST 2 is NO, so ST 3 follows and a test is carried out to see whether the command has been sent from the main controller 6 or not. In this state, "RUN" is displayed on the LCD display 11. This display indicates that the read/write control unit 4 is in the on-line state with respect to the main control device 6. In this case, even if a button of the button group 13 on the monitor unit 7 is pressed, nothing is received.

When a command is received from the main controller 6, the answer at ST 3 is YES, so that the received command is analyzed (ST 4). In response to this command, data is written into or read out of the identification unit 2 via the header 5 (ST 5). After completion of the process at ST 5, a test is made to see whether or not any error has been generated in the process (ST 6). If no error occurs, a response indicating normal termination or read data is transmitted to the main controller 6 via the interface 18 (ST 7). Then, the error LED 25 is turned off and the processing routine returns to ST 2. The occurrence or absence of errors is discriminated by reading out the data written into the identification unit 2 and comparing it with the write data in the case of the write mode. In contrast, in the case of the read mode, this distinction is made by reading the data twice from the same address in the identification unit 2 and comparing them.

If any error has occurred at ST 6, the cause of the error is analyzed (ST 9). An error code indicating the cause of the error is transmitted to the main controller 6 (ST 10). The error LED 25 lights up (ST 11). After that, the sequence routine returns to ST 2.

By switching the mode setting device 12 to the MONITOR mode, the worker in the work area where the head 5 is located can write arbitrary data to arbitrary addresses of the memory in the identification unit 2 or can read data from a arbitrary address by pressing the button group 13 on the monitor unit 7.

If the mode setting means 12 is set to the MONITOR mode, the answer at ST 2 is YES and a test is then made to see whether or not there is key input data (ST 12), thereby allowing the system to wait until any of the keys 13 of the monitor unit 7 is operated. In this state, "MONITOR" is displayed on the LCD display 11. This display content is to indicate that the group of keys 13 can be operated subsequently. When some of the keys are operated, an interrupt routine shown in Fig. 7 is started and the key matrix data of the operated keys is retrieved (ST 21).

Now, assume the case that the data is read out from the memory of the identification unit 2. When the first address to be read out is entered by using the address (ADRS) key and the numeric keys, "alF" is displayed on the LCD 11, where alF represents an address. When the operator presses the READ key 41 to execute the reading operation, the answer at ST 12 is YES, so the key input command is analyzed (ST 13). In this case, since it is assumed that the READ key 41 is pressed, "RDalF" is displayed on the LCD 11. RD represents a read command and alF represents the address.

By pressing the READ button 41, the reading operation for the identification unit 2 is carried out (ST 14). After the reading operation is completed correctly, the answer at ST 15 for checking the occurrence of errors is NO. Therefore, a code indicating a normal end or reading data is displayed on the LCD 11 of the monitor unit 7 (ST 16). In this case, "RDalFd30" is displayed on the LCD 11, where d30 indicates the reading data.

The read data is displayed and the error LED 25 is switched off (ST 17). The sequence routine then returns to ST 2.

If errors occur at ST 15, the cause of the errors is analyzed (ST 18) and an error code and an error message are displayed on the LCD display 11 of the monitor unit 7 (ST 19).

For example, in this case, "RDalFE72" is displayed on the LCD display 11. E72 indicates an error code. On the other hand, the error message "DC NOT" can be displayed optionally by shifting the display content using the key 44 or 45. The error is displayed and the error LED 25 also lights up (ST 20). Then the sequence routine jumps back to ST 2.

In the case of writing data into the identification unit 2, the address and the data to be written first are input by using the address (ADRS) key, the data (DATA) key and the numeric keys so that "alFd20" is displayed on the LCD display 11, where d20 represents data to be written.

Next, when the operator presses the WRITE key 42 to execute the write operation, the answer at ST 12 becomes YES, so that the key input command is analyzed (ST 13). For the address in the identification unit 2, "SWalF" is displayed in the write operation. SW denotes a step write command. The display of the data is cleared. After the write operation is correctly completed, "SWalFd20" is displayed and the written data content is reproduced again.

If the writing process has been terminated incorrectly, for example, "SWalFE72" is displayed on the LCD display 11. By pressing the button 44 or 45, for example, the Error message "DC NOT" is displayed. This means that the error code and error message can be displayed optionally.

An embodiment in which the processes of both procedures can be carried out in the test mode will now be described. In this embodiment, the structure shown in Figs. 1 to 5 and the procedures shown in Fig. 7 are used. The function of this embodiment, in particular the operation procedure on the part of the MPU 19, is shown in Fig. 8. In this diagram, the same procedures as those shown in Fig. 6 are designated by the same step numbers.

When the power is turned on and the operation is started, initialization is performed first (ST 1). Next, a check is made to see whether the operation mode is set to the MONITOR mode or not (ST 2). If the RUN mode is set, ST 22 follows and data is written into or read out of the identification unit 2 based on the command from the main controller 6. These operations are the same as those shown at ST 3 to ST 11 in Fig. 6.

If the operator sets the MONITOR mode by means of the mode setting device 12, the answer at ST 2 is YES, so that a check step is then performed to see whether or not key input data exists (ST 33). As described in Fig. 7, when any of the keys is pressed, the sequence routine is interrupted and the key matrix data of the pressed key is retrieved (ST 21). If the retrieved key data exists, the answer at ST 33 is YES and the key input data is analyzed (ST 34). Further, a check step is performed to see whether the pressed key is the TEST key 31 (ST 35) or the RESET key 32 (ST 42). The TEST mode is indicated by the TEST button 31 and reset (test cancellation) by the RESET button 32. If neither button 31 or 32 has been pressed, this means that a sequence other than the test sequence has been set so that data is written into or read out of the identification unit 2 using the monitor unit 7 (ST 23). This sequence corresponds to those shown at ST 13 to ST 20 in Fig. 6.

When the operator presses the TEST key 31 to adjust the distance between the head 5 and the identification unit 2, the answer at ST 35 is YES and a flag indicating that the test is being carried out is set to 1 (ST 36). At this time, "TEST 1-4" is displayed on the LCD display 11. In this display, 1-4 indicates the type of test. Namely,

1: Reading

2: Writing

3: Automatic reading

4: Automatic writing.

Each of these test types is determined by pressing a number key from the group of keys 13.

After that, the test of the specified type is started. That is, if it is NO at ST 33, a check is made to see whether the test is being carried out or not (ST 37). In this case, since the flag indicating that the test is being carried out is already set to 1, the answer at ST 37 is YES. Next, the reading or writing process for the identification unit 2 is carried out. For example, if number 1 (read) has been selected as the test type, the reading process is carried out. In this case, "TRD " is displayed. TRD indicates a test command (read) and indicates that the test is carried out. The three lower positions are intended for error display.

After the reading operation or the like is carried out at ST 38, a check is made to see whether or not errors have been generated in this step (ST 39). The generation of errors is determined by reading the data at the same address twice and comparing them in the case of, for example, the reading operation. In the case of the writing operation, the written data is read out again and compared with the data before writing. If no error is generated, the error LED 25 is turned off (ST 40). If any error has occurred, the error LED 25 is lit (ST 41) and "TRD 9E72" is displayed on the LCD 11, for example. In this way, after the TEST key 31 is operated, the command sequence of reading, writing or the like and the discrimination of error generation are repeated every second. If the above operations are performed while changing the distance between the head 5 and the identification unit 2, the write/read operation is performed correctly at the appropriate distance and no error occurs, the error LED 25 does not light up and the error indication is not displayed on the LCD 11. However, if the distance is inappropriate, the write/read operation is not performed correctly and, if errors occur, the error LED 25 lights up and the error indication is displayed on the LCD 11. Therefore, the optimal distance can be determined by merely moving the identification unit 2 while observing or monitoring the error indication.

After completion of the test, the RESET button 32 is pressed. Thus, the answer at ST 33 is YES, the answer at ST 35 is NO and the answer at ST 42 to cancel the TEST Mode YES, so that the flag indicating that the test is being performed is set to 0 (ST 43).

In the embodiment, although the error LED 25 is provided in the read/write control unit 4, it can also be provided for the head 5.

On the other hand, in the embodiment, the switching operation between the RUN mode and the MONITOR mode is performed by the mode setting means. However, if the monitor unit 7 is attached to and connected to the read/write control unit 4, the mode can be forcibly set to the MONITOR mode.

In the embodiment, one write/read control unit 4 was connected to the main control device 6. However, this invention can also be applied to the case where a plurality of write/read control units 4 are provided and connected to the main control device 6.

An embodiment particularly useful in the case where a plurality of write/read control units 4 are provided will now be described in detail. As shown by a broken line in Fig. 1, a plurality of write/read control units 4 are connected to the main control device 6 via a bus or a data transmission line. Each write/read control unit 4 is assigned a different identification number. One or more heads 5 are provided for each write/read control unit 4, and the monitor unit 7 can be attached and detachably connected to the control unit 4. The arrangement and design shown in Figs. 1 to 5 can also be used for this embodiment.

The RAM 20 in the read/write control unit 4 contains a non-volatile memory area. Errors generated when data is written into or read from the identification unit 2 are encoded each time, and the 30 error data are sequentially stored in this memory area in accordance with the order of the new data. The MPU 19 in the control unit 4 has the function of calculating the total number of occurrences of the respective errors, the total number of all errors that have occurred, and the generation ratio of the errors, and storing the calculated values in the memory, for example, RAM 20.

The operation of the object recognition system in the embodiment will now be described with reference to the flow charts shown in Figures 7 and 9. In these diagrams, the same or similar processes as those shown in Figures 6 and 8 are identified by the same reference numerals.

When the power is turned on and the operation is started, initialization is performed (ST 1). Then, it is checked whether the mode setting means 12 has been set to the RUN mode or the MONITOR mode (ST 2). Now, assume that the mode setting means 12 has been set to the RUN mode and the read/write control unit 4 is connected to the main controller 6. In this case, the sequence routine advances to ST 3 and a check is made to see whether or not a command has been received from the main controller 6. If the self-number has been set by the main controller 6 and a command for writing data into or reading data from the identification unit 2 is sent, the answer at ST 3 is YES. The received command is analyzed (ST 4). Then, a check is made to see whether this command meets the writing or reading operation for the identification unit 2 or not (ST 51). In the case of the ordinary writing or reading operation as shown in the foregoing embodiment, data is written into or read out from the identification unit 2 according to the command (ST 5). Each time the writing or reading operation is completed, a check is made to see whether or not errors have occurred (ST 6). If any error has occurred, the error data is processed (ST 9). That is, the error is encoded after each type of error and stored in the RAM 20. An error response is returned to the main controller (ST 10). In contrast, if no error occurs at ST 6, a normal end response indicating that the writing or reading operation has been correctly completed is returned to the main controller 6 (ST 7). The operation of the error LED 25 is omitted here.

As a result of the analysis of the command at ST 51, if the command does not indicate a write/read operation for the identification unit, ST 52 follows, and a check operation is performed to see whether the error data is monitored or not. If the command from the main control device 6 indicates monitoring of the error data, the error data stored in the memory 20 of the write/read control unit 4 is sequentially returned to the main control device 6 in response to this command (ST 53). Thus, the main control device 6 can collect the error data stored in the write/read control unit 4.

If the command indicates neither any of the write/read operations for the identification unit 2 nor the error data monitoring, ST 56 follows to see whether the command means erasing the error data or not. If the command indicates that the error data should be erased, the data up to All error data stored in the RAN 20 in the control unit 4 are then deleted (ST 57). The sequence routine then returns to ST 2.

Next, in case of monitoring the error data by the monitor unit 7, the mode setting means 12 is set to the MONITOR mode. Thus, the answer at ST 2 is YES and ST 12 follows to see whether there is key input data or not. The discrimination as to the presence or absence of the key input data is made by means of the interrupt routine shown in Fig. 7. The type of the operated key is determined by the data retrieved by the interrupt routine (ST 13). If the operated key is not the error (ERR) key 33, the answer at ST 54 is NO. Then, a check is made to see whether the operated key is the clear (CLR) key 43 or not (ST 56). However, if the operated key is not the clear key 43, the answer at ST 56 is NO. In this case, the write/read operation for writing the data into the identification unit 2 or reading the data from the identification unit 2, the test mode operation or the like is carried out as mentioned in the above embodiment. After that, the operation routine returns to ST 2. The error data generated in the write/read operation is also stored in the RAM 20.

As a result of the analysis of the key input data, if the pressed key is the error key 33, the answer at ST 54 is YES. Therefore, the error data stored in the RAN 20 of the read/write control unit 4 are read out sequentially and displayed sequentially on the LCD display 11 of the monitor unit 7. Thus, the operator can determine what kind of error data has occurred in the read/write control unit 4 in the past time. In the case where the error data is stored for a certain period of time, period of time and to delete the error data obtained up to that point, the operator must press the delete key 43. Therefore, the answer at ST 56 is YES and the error data stored up to that point in the RAM 20 of the control unit 4 are deleted (ST 57).

An example of the display in the case where the error data is monitored in the monitor unit 7 is explained below.

If the operator presses the Error (ERR) button 33 during the MONITOR mode, "ERROR1-4" is displayed on the LCD display 11.

This display content indicates that the selection of the contents from error states 1 to 4 is to be made. When the digit 1 is designated by a numeric key of the keys 13, the most recently occurred error data value (among 30 errors) is designated. When the digit 2 is designated, a statistical error data value is designated. When the digit 3 is designated, the most recently obtained error data value is cleared. When the digit 4 is designated, the statistical error data value is cleared. When the RESET key 32 is pressed, the end of the error data display is displayed. When the operator presses the numeric key 1 following the error (ERR) key 33, that is, when the operator specifies to display the most recently obtained error data value, "N01RD110" is displayed on the LCD display 11. N01 indicates the error generation sequence number. The number of the generation order of the most recently occurred error data value takes "01", that of the oldest error data value takes "30". On the other hand, RD represents an error generation command and "1" indicates the transmission path number and "10" represents the error code number. The error code display and the error message display can be switched optionally by the keys 44 or 45. The error message "H.PARITY" is displayed by pressing the 44 or 45 key for the example of the above-mentioned error. By pressing the 44 or 45 key again, the original display content "N01RD110" can be displayed. Furthermore, by pressing the ZUN key 47 to display the error data of the next order, "N02RD170" is displayed, for example. To display the original data again, pressing the ABN keys 46 displays "N01RD110". By pressing the ZUN key 47 or the ABN key 46, the error data can be shifted forward or backward as desired.

In the case of the statistical error data, "87-09-30" is displayed. In this case, the year, month and day of the start date are displayed to obtain the statistical error data. When the ZUN key 47 is pressed, the next content is displayed and, for example, "SZZ9 110" is displayed. ZZ9 indicates the number of occurrences of the errors. "1" in the third place indicates the transmission path number and "10" represents the error code. By pressing the 44 or 45 key, the error message corresponding to the error code currently displayed is displayed. On the other hand, by pressing the ZUN key 47, the next statistical errors are displayed sequentially in accordance with the order of the error code. Similarly, by pressing the ABN key 46, the statistical errors can be displayed in reverse sequential order. After all statistical errors have been displayed, the display progresses and the MCBF value obtained by calculating the following equation is displayed.

MCBF = Total number of higher commands/Total number of higher and lower transmission errors.

Next, in the case of deleting the most recently occurred error data value, "DELETE NO?" is displayed to confirm the execution of the deletion. In this case, pressing the SET key 48 executes the deletion. At this time, pressing the RESET key 32 can also cancel the deletion. In the case of deleting the statistical error data value, "DELETE NO?" is displayed to confirm the execution of the deletion. When the operator presses the SET key 48, the deletion is executed.

Claims (8)

1. An object detection system comprising: - an identification unit (2) which is attached to an object (1) to be recognized for storing identification data of the object; - a head (5) for writing or reading predetermined data into or from the identification unit in a contactless manner; and - a write/read control unit (4) for controlling the write/read operations of data into or from the identification unit (2) via the head (5) in accordance with a command from a main control device (6); where - the read/write control unit (4) is detachably connected to a monitor unit (7) which is equipped with a group of input keys (13) and a display device (11); - the monitor unit (7) has an operating mode setting device (12) for selecting a first or second operating mode and a key input device (13) for entering commands and data relating to the write and read operations for the identification unit (2); and - the write/read control unit (4) comprises means (19) for controlling the write/read operations of data into or out of the identification unit based on the command from the main control device (6) in response to the selection of the first operating mode and based on the command input via the key input device (13) in response to the selection of the second operating mode. 2. An object detection system comprising: - an identification unit (2) which is attached to an object (1) to be recognized for storing identification data of the object; - a head (5) for writing or reading predetermined data into or from the identification unit in a contactless manner; and - a write/read control unit (4) for controlling the write/read operations of data into or from the identification unit (2) via the head (5) in accordance with a command from a main control device (6); where - the read/write control unit (4) is detachably connected to a monitor unit (7) which is equipped with a group of input keys (13) and a display device (11); - the monitor unit (7) has a key input device (13) which includes a key (31) for determining a test mode and keys (41, 42) for entering commands related to the write/read operations for the identification unit (2); and - the write/read control unit (4) comprises means (19) for controlling the continuous execution of the write/read operations for the identification unit (2) in response to the determination of the test mode in the monitor unit (7) and means (19) for discriminating whether each of the write/read operations has been correctly performed or not and for enabling the result of the discrimination to be displayed on the display means (11). 3. An object detection system comprising: - an identification unit (2) which is attached to an object (1) to be recognized for storing identification data of the object; - a head (5) for writing or reading predetermined data into or from the identification unit in a contactless manner; and - a write/read control unit (4) for controlling the write/read operations of data into or from the identification unit (2) via the head (5) in accordance with a command from a main control device (6); where - the read/write control unit (4) is detachably connected to a monitor unit (7) which is equipped with a group of input keys (13) and a display device (11); - the write/read control unit (4) has means (19) for distinguishing whether or not errors were generated during the write/read operations of data into or from the identification unit (2), and a storage device (20) for sequentially storing the distinguished errors; and - the error data in the storage device (20) are displayed on the display device (11) in the monitor unit (7). 4. A system according to claim 3, wherein the error data stored in the storage device (20) are displayed on the display device (11) upon command of a key (44, 45). 5. A system according to claim 3, wherein the error data stored in the storage device (20) are automatically displayed on the display device (11) after being differentiated by the devices (19). 6. A system according to claim 3, wherein the means (19) for distinguishing the errors comprise integrated circuits for calculating the total number of occurrences of different errors, the total number of all errors that have occurred and the statistical analysis of the errors. 7. A system according to claim 6, wherein the means (19) for collecting the error data are sequentially connected to the main control device (6). 8. A method for testing the system according to claim 2, wherein after determining the test mode by means of the key (31), the write/read operations are repeated several times by the write/read control unit (4) while the distance between the head (5) and the identification unit (2) is adjusted until no error indication is observed.