Claims
- 1. A programmable controller having a power source module, a CPU module, an input module and an output module,said programmable controller comprising: an output circuit portion provided in said output module, a current detection portion for detecting a current flowing in said output circuit portion, and having a plurality of resistors connected in series and each with a different resistance value and a plurality of switches connected in parallel to said plurality of resistors, respectively, to set a voltage by a change-over and a combination of said switches, a reference voltage variation portion for setting a reference voltage of a comparator circuit variable, said comparator circuit comparing said reference voltage with a voltage of said current detection portion; an overcurrent control circuit portion for supplying an interruption signal to said output circuit portion when a detected current value exceeds a predetermined value, and an overcurrent indication portion for operating synchronously with said interruption signal, wherein when an overcurrent flows in said output circuit portion, said overcurrent is interrupted, a value of said overcurrent interrupted is continuously variable based on said reference voltage variation portion, and said overcurrent indication portion indicates an interruption of said overcurrent.
- 2. A programmable controller having an output module, the controller comprising:an output circuit portion provided in said output module; a current detection portion to detect current flowing in said output circuit portion and having a plurality of resistors connected in series and each with a different resistance value and a plurality of switches connected in parallel to said plurality of resistors, respectively, to set a voltage by a change-over and a combination of said switches; a reference voltage variation portion to variably set a reference voltage of a comparator circuit, said comparator circuit comparing said reference voltage with a voltage of said current detection portion; an overcurrent control circuit portion to supply an interruption signal to said output circuit portion based on an output of said comparator circuit; and an overcurrent indication portion to operate based on said interruption signal, wherein when an overcurrent flows in said output circuit portion, said overcurrent is interrupted and said overcurrent indication portion indicates an interruption of said overcurrent.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-014149 |
Jan 2000 |
JP |
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Parent Case Info
This is a continuation of application Ser. No. 09/761,183, filed Jan. 18, 2001, the entire disclosures of which are hereby incorporated by reference.
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Number |
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Date |
Kind |
4272816 |
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Jun 1981 |
A |
4720758 |
Winslow |
Jan 1988 |
A |
4937697 |
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Jun 1990 |
A |
Non-Patent Literature Citations (2)
Entry |
PCIM'88 Proceedings p. 35, No month. |
Warren Schultz, Motorola, SPS Lossless Current sensing with SENSEFETs Enhances Motor Drive Design (Cover Sheet), No date. |
Continuations (1)
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Number |
Date |
Country |
Parent |
09/761183 |
Jan 2001 |
US |
Child |
09/986590 |
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US |