JPS57159303A - Triplex system transmission circuit - Google Patents

Triplex system transmission circuit

Info

Publication number
JPS57159303A
JPS57159303A JP4393681A JP4393681A JPS57159303A JP S57159303 A JPS57159303 A JP S57159303A JP 4393681 A JP4393681 A JP 4393681A JP 4393681 A JP4393681 A JP 4393681A JP S57159303 A JPS57159303 A JP S57159303A
Authority
JP
Japan
Prior art keywords
signal
signals
output
circuit
outputted
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP4393681A
Other languages
Japanese (ja)
Other versions
JPH0219481B2 (en
Inventor
Akihisa Kaihara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP4393681A priority Critical patent/JPS57159303A/en
Publication of JPS57159303A publication Critical patent/JPS57159303A/en
Publication of JPH0219481B2 publication Critical patent/JPH0219481B2/ja
Granted legal-status Critical Current

Links

Landscapes

  • Safety Devices In Control Systems (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

PURPOSE: To transmit a normal signal to a system at all times, by securing a transmission circuit output always in normal operation as a final output, even if a triplex system transmission circuit is in failure for one circuit system.
CONSTITUTION: In transmitting a signal of a detector 1 as an output signal 3, a signal having an output of an A signal transmission circuit 10 at an attenuator 11 is taken as the signal A. Similarly, signals B and C are outputted from each transmission line, the signals AWC are summed at adders 12, 22 and 32 through combination, and a=C+A, b=A+B and c=B+C are operated. The signals aWc are inputted to a high value selecting circuit 51 and a low value selecting circuit 52. When a signal BH higher than a normal signal is outputted by the signal B, the signals b and c go to high to output signals bH and cH. On the other hand, a signal BL lower than the normal signal is outputted, then the signals b and c output signals bL and cL. In this case, the output (a) is the normal signal aO. Thus, the signal aO is outputted from the circuit 52 as a signal 3 in case of failure toward the BH and the signal aO is outputted from the circuit 51 in case of failure toward the CH.
COPYRIGHT: (C)1982,JPO&Japio
JP4393681A 1981-03-27 1981-03-27 Triplex system transmission circuit Granted JPS57159303A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4393681A JPS57159303A (en) 1981-03-27 1981-03-27 Triplex system transmission circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4393681A JPS57159303A (en) 1981-03-27 1981-03-27 Triplex system transmission circuit

Publications (2)

Publication Number Publication Date
JPS57159303A true JPS57159303A (en) 1982-10-01
JPH0219481B2 JPH0219481B2 (en) 1990-05-02

Family

ID=12677573

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4393681A Granted JPS57159303A (en) 1981-03-27 1981-03-27 Triplex system transmission circuit

Country Status (1)

Country Link
JP (1) JPS57159303A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011107807A (en) * 2009-11-13 2011-06-02 Hitachi Ltd Process control device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011107807A (en) * 2009-11-13 2011-06-02 Hitachi Ltd Process control device

Also Published As

Publication number Publication date
JPH0219481B2 (en) 1990-05-02

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