Sending device, receiving device, communication control device, communication system, and communication control method

Abstract

The system has, provided in a sending device, a generator generating transmission data including data, a data error detection code generated from the data and a safety flag indicating a degree of reliability, and transmission data; has, provided in a receiving device, a plurality of components of extracting transmission data, a safety flag, and a data error detection code from a received frame, and detecting a data error, a comparator comparing the matching of a plurality of received frames, and a selector selecting one received frame, from the frame error detection result, the safety flag, the data error detection result, and the matching comparison result; and determines the validity of transmitted data by the detection corresponding to the degree of reliability set with the safety flag.

1 . A receiving device comprising:
 a receiver receiving a frame including data and safety flag information indicating a safety level;   an extractor extracting data and safety flag information from said frame;   and a detector performing detection of communication errors in said received data; and   wherein an error detection code is included in said frame; and a matching comparison is performed, in said communication error detection, of at least part of the information of said received frame and said received error detection code.   
   
   
       2 . The receiving device in  claim 1 , wherein said frame, along with including a packet, has a packet error code included which corresponds to said packet in case said safety flag information indicates that the safety level is relatively high. 
   
   
       3 . The receiving device in  claim 1 , wherein receiving at least two frames including substantially the same data in case the safety level is relatively high. 
   
   
       4 . The receiving device in  claim 3 , further comprising at least two reception buffers and wherein the data of said at least two frames are respectively stored in said at least two reception buffers. 
   
   
       5 . The receiving device in  claim 3 , wherein mutually comparing the matching of said at least two reception buffers in case the safety level is relatively high. 
   
   
       6 . The receiving device in  claim 1 , using a preset safety output value in substitution for said communication data when a failure has occurred in said communication. 
   
   
       7 . The receiving device in  claim 6 , wherein a validity flag is included in said frame and characterized by using said safety output value in response to the state of said validity flag. 
   
   
       8 . The receiving device in  claim 1 , comparing the matching, regarding said at least two frames including substantially the same data, of all their bits in case the safety level is relatively high, and using one of said received data items as the data in case all bits coincide. 
   
   
       9 . A communication control method comprising the steps of:
 sending data to a sending destination communication control device via communication lines which at least in part have serial transmission;   receiving said sent data from said sending destination control device via said communication lines;   comparing the matching of said sent data and said received data; and   sending, based on said matching comparison result, output permission information indicating permission to output said previously sent data to said sending destination communication control device via said communication lines.   
   
   
       10 . A communication control method comprising the steps of:
 sending control data controlling a control object to a sending destination communication control device via communication lines which at least in part have serial transmission;   receiving said sent control data from said sending destination control device via said communication lines;   comparing the matching of said sent control data and said received control data; and   sending, based on said matching comparison result, output permission information indicating permission to output, with respect to the control object, said previously sent control data to said sending destination communication control device via said communication lines.   
   
   
       11 . A communication control method comprising the steps of:
 sending control data controlling a control object, together with communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source, with respect to a sending destination communication control device via communication lines which at least in part have serial transmission;   receiving said sent control data, together with communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source, from said sending destination control device via said communication lines;   comparing the matching of said sent control data and said received control data, together with communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source; and   sending, based on said matching comparison result, output permission information indicating permission to output, with respect to the control object, said previously sent control data with respect to said sending destination communication control device via said communication lines.   
   
   
       12 . The communication control method in  claim 11 , wherein information is received from the sending destination communication control device regarding the execution of the output. 
   
   
       13 . The communication control method in  claim 11 , wherein, after receiving from the sending destination communication control device a signal indicating a request to send, control data controlling said control object are sent. 
   
   
       14 . The communication control method in  claim 11 , wherein safety flag information is included in the sending information and the reception information, and said sending destination communication control device sends the information in response to said safety level. 
   
   
       15 . The communication control method in  claim 11 , wherein, based on said matching comparison result, communication is halted in case said sent data and said received data do not coincide. 
   
   
       16 . A communication control device, comprising the steps of:
 a first sender sending control data controlling a control object, together with communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source, with respect to a destination communication control device via communication lines which at least in part have serial transmission;   a receiver receiving said sent control data, together with communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source, from said sending destination control device via said communication lines;   a matching comparator comparing the matching of said sent control data and said received control data, together with communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source; and   a second sender sending, based on said matching comparison result, output permission information indicating permission to output, with respect to the control object, said previously sent control data with respect to said sending destination communication control device via said communication lines.   
   
   
       17 . A communication control system, wherein:
 a sending source communication control device receives said sent control data, together with communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source, from said sending destination control device via said communication lines;   said sending destination control device sends, with respect to said sending source communication control device, via said communication lines, said received control data, together with communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source; and   said sending source communication control device compares the matching of the sent control data and the received control data, together with comparing the matching of communication destination identifying information indicating the communication destination and communication source identifying information indicating the communication source, and, based on said matching comparison result, sends output permission information indicating permission to output, with respect to the control object, said previously sent control data to said sending destination communication control device via said communication lines.   
   
   
       18 . A sending control device, comprising:
 a receiver receiving data indicating a relative safety level;   a code generator generating error codes respectively for a plurality of data units;   a data generator generating data from said respective error codes added in case a plurality of data units, and said data units, have relatively high safety; and   an adder generating an error code regarding at least part of said generated data and adding said generated data.   
   
   
       19 . The sending control device in  claim 18 , wherein status information reflecting an error occurrence state of the communication process is included in said data. 
   
   
       20 . The sending control device in  claim 19 , wherein a controller and a process input/output device communicate via a communication device, and characterized by having: a function reflecting error occurrence information in the status information of the format of the communication data, in case an error has occurred in any one of said controller, said communication device, and said process input/output device. 
   
   
       21 . The sending control device in  claim 20 , wherein
 said error code is a CRC code;   and characterized by:   having registers in the status portion of said communication data format, in a number equal to or greater than the number of devices performing CRC checks of data sending and reception in said process input/output device, from said controller; and   recording the CRC error occurrence state of each device individually in said registers.   
   
   
       22 . The sending control device in  claim 21 , further comprising: CRC check circuits checking the CRC code generated in said controller and said process input/output device and registers reflecting the check results;
 and having a function reflecting, in said status information, the CRC check result.   
   
   
       23 . The sending control device in  claim 18 , further comprising having a parallel bus for sending and receiving said CRC codes. 
   
   
       24 . The sending control device in  claim 18 , wherein said error code is a CRC code and characterized by: having an operating mode control circuit enabling switching between validity and non validity of CRC generation and the CRC check function with respect to an input/output signal. 
   
   
       25 . The sending control device in  claim 18 , further comprising a function of making a comparative check of a preset operating mode and an operating mode on the data output side reflected in the status information. 
   
   
       26 . The sending control device in  claim 18 , wherein a controller and a process input/output device communicate via a communication device; wherein said error code is a CRC code; and characterized by:
 generating, with said CRC generation circuit, a CRC code with respect to data introduced simultaneously with the introduction of a process input signal;   storing the CRC code in a register simultaneously with said process input signal; and   simultaneously sending, in the communication between said communication device and said process input/output device, said process input data and said CRC code to the communication device.   
   
   
       27 . A reception control device, comprising:
 a receiver receiving data indicating a relative safety level;   a judger judging, from a received error code, whether the received frame has an error or not; and   a judger judging, in case units of said data have a relatively high degree of safety, whether the unit data, regarding the respective unit data included in said received frame, have an error or not, from the corresponding plural error codes.   
   
   
       28 . A communication system having a sending device and a receiver device receiving a sent frame from said sending device, wherein said sending device comprising:
 a receiver receiving data indicating a relative level of safety;   a code generator generating error codes respectively for a plurality of data units;   a data generator generating data from data indicating said relative level of safety, a plurality of data units, and said respective error codes added in case said data units have a relatively high degree of safety; and further,   an adder generating an error code regarding at least part of said generated data and adding said generated data; and   said receiving device consists in having:   a receiver receiving data indicating a relative level of safety;   a first judger judging from the received error code whether the received frame has an error or not; and   a second judger judging, in case units of said data have a relatively high degree of safety, whether the unit data, regarding the respective unit data included in said received frame, have an error or not, from the corresponding plural error codes.