JPS6438846U - - Google Patents

Info

Publication number
JPS6438846U
JPS6438846U JP1987133916U JP13391687U JPS6438846U JP S6438846 U JPS6438846 U JP S6438846U JP 1987133916 U JP1987133916 U JP 1987133916U JP 13391687 U JP13391687 U JP 13391687U JP S6438846 U JPS6438846 U JP S6438846U
Authority
JP
Japan
Prior art keywords
current
operational amplifier
output
value
holding
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
JP1987133916U
Other languages
English (en)
Other versions
JPH0633723Y2 (ja
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 filed Critical
Priority to JP1987133916U priority Critical patent/JPH0633723Y2/ja
Priority to US07/237,107 priority patent/US4959649A/en
Publication of JPS6438846U publication Critical patent/JPS6438846U/ja
Application granted granted Critical
Publication of JPH0633723Y2 publication Critical patent/JPH0633723Y2/ja
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
    • G08C19/00—Electric signal transmission systems
    • G08C19/02—Electric signal transmission systems in which the signal transmitted is magnitude of current or voltage

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Selective Calling Equipment (AREA)

Description

【図面の簡単な説明】
第１図は本考案に係る電流保持回路の一実施例
を示す回路構成図、第２図はこの電流保持回路に
おけるサンプルホールド回路の他の実施例を示す
図、第３図は２線式計器の構成および通信装置の
接続状態を示す回路図である。 １……発信器、１０……電流保持回路、１１…
…基準抵抗、１２……電流検知回路、１３……サ
ンプルホールド回路、Ｒ……受信抵抗、Ａ１，Ａ
２……オペアンプ、Ｃ……コンデンサ、Ｓ１〜Ｓ
３……切換スイツチ、Ｑ……ＮＰＮトランジスタ
。

Claims (1)

    【実用新案登録請求の範囲】
  1. ループ電流値を電圧値に変換する基準抵抗とこ
    の基準抵抗の変換する電圧値をその非反転入力と
    する演算増幅器とを備えてなる電流検知手段と、
    この電流検知手段の出力値をホールドするサンプ
    ルホールド手段と、このサンプルホールド手段の
    出力を前記演算増幅器の反転入力としこの演算増
    幅器の出力に基づいて前記ループ電流を制御しこ
    のループ電流を一定値に保持する電流制御手段と
    を備えてなる電流保持回路。
JP1987133916U 1987-09-03 1987-09-03 通信装置 Expired - Lifetime JPH0633723Y2 (ja)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP1987133916U JPH0633723Y2 (ja) 1987-09-03 1987-09-03 通信装置
US07/237,107 US4959649A (en) 1987-09-03 1988-08-26 Current holding circuit of two-wire instrument

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1987133916U JPH0633723Y2 (ja) 1987-09-03 1987-09-03 通信装置

Publications (2)

Publication Number Publication Date
JPS6438846U true JPS6438846U (ja) 1989-03-08
JPH0633723Y2 JPH0633723Y2 (ja) 1994-08-31

Family

ID=15116086

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1987133916U Expired - Lifetime JPH0633723Y2 (ja) 1987-09-03 1987-09-03 通信装置

Country Status (2)

Country Link
US (1) US4959649A (ja)
JP (1) JPH0633723Y2 (ja)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0695439B2 (ja) * 1989-09-26 1994-11-24 アナログ・ディバイセス・インコーポレーテッド 電流モードサンプルアンドホールド増幅器
EP0495001B1 (en) * 1989-10-02 1999-02-17 Rosemount Inc. Field-mounted control unit
US5434774A (en) * 1994-03-02 1995-07-18 Fisher Controls International, Inc. Interface apparatus for two-wire communication in process control loops
EP2352134B1 (en) * 2008-10-02 2018-09-05 Hochiki Corporation Transmission input circuit
WO2011090486A1 (en) * 2010-01-22 2011-07-28 Hewlett-Packard Development Company, L.P. I/o control systems and methods
CN115327215B (zh) * 2022-08-22 2023-08-08 北京思凌科半导体技术有限公司 电流检测装置及电流检测***

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE30597E (en) * 1967-08-21 1981-05-05 Rosemount Inc. Two wire current transmitter responsive to a resistive temperature sensor input signal
DE2445337C2 (de) * 1974-09-23 1986-05-15 Philips Patentverwaltung Gmbh, 2000 Hamburg Schaltungsanordnung zur Übertragung von elektrischen Meßwertsignalen
US4401974A (en) * 1979-02-12 1983-08-30 Motorola, Inc. Digital sample and hold circuit
CA1173927A (en) * 1981-11-02 1984-09-04 Felix J. Houvig Communication system and method
WO1985004750A1 (en) * 1982-11-26 1985-10-24 Mitsubishi Denki Kabushiki Kaisha Analog input circuit
JPS63232694A (ja) * 1987-03-20 1988-09-28 Yamatake Honeywell Co Ltd 通信装置

Also Published As

Publication number Publication date
US4959649A (en) 1990-09-25
JPH0633723Y2 (ja) 1994-08-31

Similar Documents

Publication Publication Date Title
JPS6438846U (ja)
JPH0342527U (ja)
JPS63187443U (ja)
JPS61614U (ja) 出力電圧制限回路
JPH0352643U (ja)
JPS62158919U (ja)
JPH0438538U (ja)
JPH0386489U (ja)
JPS58187772U (ja) 信号出力検知回路
JPS63151016U (ja)
JPH0361540U (ja)
JPS63138746U (ja)
JPH01127097U (ja)
JPS6273629U (ja)
JPS63177000U (ja)
JPH03130100U (ja)
JPS62129820U (ja)
JPS60158162U (ja) 抵抗測定装置
JPS61168710U (ja)
JPS596738U (ja) 電子体温計
JPS62178639U (ja)
JPS6390341U (ja)
JPS62165728U (ja)
JPH02135871U (ja)
JPH034278U (ja)