Title:
COMMUNICATION FOR POWER SUPPLY TYPE FIELD INSTRUMENT
Document Type and Number:
Japanese Patent JP3299556
Kind Code:
B2
Abstract:
PURPOSE: To eliminate a need to connect an external power source and a voltage drop element to a field instrument and to improve the efficiency of maintenance and inspection work of the field instrument by incorporating a power supply circuit, which supplies power to the field instrument, and the voltage drop element in a communicator and providing an inter-terminal voltage measuring circuit of the voltage drop element.
CONSTITUTION: Power is supplied to a communicator 2 from an incorporated power supply circuit 212, and it is subjected to voltage conversion by a DC-DC converter 201 and is supplied to the field instrument through a transmission line 5. User information inputted to an input device is sent to the transmission line 5 through a transmission/reception circuit 205, and a response signal from the field instrument corresponding to this information is displayed on a display device 207 through a demodulating circuit 209 and an I/O 206. The field instrument measures a detected signal of the temperature of various plants or the like by the terminal voltage of a voltage drop element, which is connected in parallel with the transmission line 5, to obtain a physical quantity. Thus, the field instrument is efficiently maintained and inspected.
Inventors:
Yukio Ito
Makoto Kogure
Makoto Kogure
Application Number:
JP23929991A
Publication Date:
July 08, 2002
Filing Date:
September 19, 1991
Export Citation:
Assignee:
株式会社日立製作所
株式会社日立サイエンスシステムズ
株式会社日立サイエンスシステムズ
International Classes:
G08C19/02; H04Q9/00; (IPC1-7): H04Q9/00
Domestic Patent References:
| JP3129929A | ||||
| JP3156700A | ||||
| JP298237A |
Attorney, Agent or Firm:
Yasuo Sakuta