CN105320056A - Terminal resistor automatic matching system and method of PLC expansion buses - Google Patents
Terminal resistor automatic matching system and method of PLC expansion buses Download PDFInfo
- Publication number
- CN105320056A CN105320056A CN201510619901.3A CN201510619901A CN105320056A CN 105320056 A CN105320056 A CN 105320056A CN 201510619901 A CN201510619901 A CN 201510619901A CN 105320056 A CN105320056 A CN 105320056A
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- Prior art keywords
- bus
- expansion
- plc
- expansion module
- closed switch
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/05—Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
- G05B19/052—Linking several PLC's
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/10—Plc systems
- G05B2219/11—Plc I-O input output
- G05B2219/1109—Expansion, extension of I-O
Abstract
The invention discloses a terminal resistor automatic matching system of PLC expansion buses. The system comprises a PLC and a plurality of expansion modules. The PLC and the plurality of expansion modules are cascaded through the expansion buses to form a bus topological structure, wherein each expansion module is provided with a frontward bus interface and a backward bus interface, the backward bus interface is provided with a normally-closed switch, and the normally-closed switch is in parallel connection with a normally-closed switch and connects a terminal resistor to the expansion bus; and when a cable is inserted in the backward bus interface, the cable is abutted against the normally-closed switch to enable the normally-closed switch to be open. The invention discloses a corresponding method. By adopting the technical scheme provided by the invention, the terminal resistors can be automatically and rapidly matched.
Description
Technical field
The present invention relates to programmable logic controller (PLC) (ProgrammableLogicController, PLC) field, particularly relate to a kind of terminal resistance automatic patching system and method for PLC expansion bus.
Background technology
In the prior art, PLC is expansion I/O (Input/Output, input or output) point or function, generally need various I/O module or functional module to be coupled together formation PLC control system by expansion bus, PLC is communicated with I/O module or functional module by this expansion bus.
Such as Serial Peripheral Interface (the serialperipheralinterface adopted between existing PLC and expansion module, or Controller Area Network BUS (ControllerAreaNetwork SPI), etc. CAN) expansion bus carries out connecting and communicating, in a particular application, before PLC communicates with expansion module, need the matching process of terminal resistance.Wherein, terminal resistance is the resistance on a pair order wire of the far-end (in two communication port of lie farthest away) being connected in parallel on bus topolopy, and its effect is to eliminate the signal reflex in the communications cable, effectively strengthening signal intensity.But in prior art, carry out in the system of cascade at PLC and expansion module, need which rank of expansion module of artificial judgment to be the expansion module of afterbody, and be manually connected in the terminal resistance at this expansion module place.
Summary of the invention
In view of the deficiencies in the prior art, the terminal resistance automatic matching method of a kind of PLC expansion bus of the embodiment of the present invention and system, automatically can identify afterbody expansion module in PLC control system, and automatically realize the coupling of terminal resistance.
In order to reach foregoing invention object, embodiments provide a kind of terminal resistance automatic patching system of PLC expansion bus, it comprises PLC and multiple expansion module, and described PLC and described multiple expansion module form bus topolopy by expansion bus cascade, wherein:
Each expansion module all has a forward direction bus interface and a backward bus interface, is provided with normally closed switch in the rear in bus interface, and described and described normally closed switch is in parallel and is connected a terminal resistance extremely described expansion bus;
When described backward bus interface inserts cable, then support described normally closed switch and make it disconnect.
Preferably, the backward bus interface of each expansion module described comprises:
Female body, it is the framework of one end open, is provided with the multiple terminals penetrating this body in it, is provided with a normally closed switch between described multiple terminal, and the sidewall of described female body leads to buckle 44;
A sidewall of described female body is provided with a locating slot.
Preferably, the cable be connected with described backward bus interface has a cable connector, and it comprises:
Male body, one end is provided with multiple terminal hole, is provided with a normally closed switch hole between terminal hole, a sidewall of described male body is provided with one with the locating piece matched with described locating slot.
Preferably, described expansion bus is MLVDS(MultipointlowVoltageDifferentialSignaling, multiple spot low-voltage differential signal) bus.。
Correspondingly, the embodiment of the present invention additionally provides a kind of terminal resistance automatic matching method of PLC expansion bus, and be applied in the terminal resistance automatic patching system of aforesaid PLC expansion bus, the method comprises the steps:
PLC is connected by order of cables with multiple expansion module;
In bus topolopy, when the forward direction bus interface and backward bus interface of expansion module at the corresponding levels are all inserted into cable, then the upper normally closed switch of described expansion module is opened, and terminal resistance and the expansion bus of described expansion module at the corresponding levels disconnect;
In bus topolopy on afterbody expansion module, its backward bus interface is not inserted into cable, the normally closed switch of last expansion module described is in closure state, then the terminal resistance in afterbody expansion module is connected with expansion bus, on Auto-matching to described expansion bus.
Implement the embodiment of the present invention, there is following beneficial effect:
The technical scheme that the embodiment of the present invention provides, all arrange a normally closed switch, and terminal resistance is connected on expansion bus by this normally closed switch by rear in each expansion module of the PLC system by expansion bus cascade in bus interface; When after each expansion module cascade, the expansion module mediated, because its backward bus interface is inserted into cable, makes the normally closed switch of its correspondence disconnect, thus the terminal resistance on expansion module at the corresponding levels and expansion bus is disconnected; And for last expansion module, because its backward bus interface is not inserted into cable, therefore the normally closed switch of its correspondence is in closure state, therefore can by terminal resistance Auto-matching to expansion bus.In the program, can rapidly and accurately by terminal resistance Auto-matching on expansion bus.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the structural representation of a terminal resistance automatic patching system embodiment of a kind of PLC expansion bus provided by the invention;
Fig. 2 is the connection diagram of expansion module terminal resistance in a first situation in Fig. 1;
Fig. 3 is the connection diagram of expansion module terminal resistance in this case in Fig. 1;
Fig. 4 is the connection diagram of expansion module terminal resistance in a third situation in Fig. 1;
Fig. 5 is the structural representation that the backward bus interface of expansion module is connected with cable;
Fig. 6 is the structural representation of backward bus interface;
Fig. 7 is the structural representation of cable connector;
Fig. 8 is cable connector longitudinal profile schematic diagram in the pre-connection in backward bus interface in Fig. 6 and Fig. 7;
Fig. 9 is cable connector longitudinal profile schematic diagram upon connection in backward bus interface in Fig. 6 and Fig. 7;
Figure 10 is the main flow schematic diagram of an embodiment of the terminal resistance automatic matching method of a kind of PLC expansion bus provided by the invention.
Embodiment
Below in conjunction with accompanying drawing, explanation is referred to embodiments of the invention.
As shown in Figure 1, the structural representation of a terminal resistance automatic patching system embodiment of a kind of PLC expansion bus provided by the invention is shown.In this embodiment, the terminal resistance automatic patching system of this PLC expansion bus comprises PLC1 and adopts expansion bus to carry out cascade between multiple expansion module 2, PLC1 and multiple expansion module 2; Wherein, in one embodiment, this expansion bus adopts MLVDS bus, it belongs to bus type topological structure half-duplex operation, the expansion bus mentioned below is all described with MLVDS expansion bus, when being understandable that, in other examples, the bus of other types can also be adopted.Expansion module 2 adopts cascade system, and each expansion module is all independently individual, and also do not have priority, but each expansion module 2 possesses independently address, in one example in which, PLC can cascade 8 expansion modules.In this bus type topological structure, PLC serves as host role, and expansion module serves as from machine role, and bus interface comprises expansion bus clock, expansion bus data and address wire etc.Wherein expansion bus clock sends by PLC is leading, and expansion module carries out exchanges data by the beat of this expansion bus clock.In some instances, can to reach 55MHz even higher for this clock frequency.Particularly, each expansion module 2 has a forward direction bus interface and a backward bus interface, and wherein, forward direction bus interface connects forward expansion module 2 above or PLC, and backward bus interface connects expansion module 2 below backward.
As shown in Figure 2, then the connection diagram of the terminal resistance in a first situation of expansion module in the embodiment of the present invention is shown; In this embodiment, each expansion module all has a forward direction bus interface and a backward bus interface, and in bus interface, be provided with normally closed switch K1 rear, K1 is in parallel with normally closed switch K1, and connects a terminal resistance R1 to expansion bus;
Wherein, K1 and normally closed switch K1 is normally closed switch, and when the first situation, when namely its forward direction bus interface and backward bus interface all do not insert cable, K1 and normally closed switch K1 is in closure state, and this terminal resistance R1 is connected to expansion bus.
As shown in Figure 3, then the connection diagram of the terminal resistance in this case of expansion module in the embodiment of the present invention is shown; It illustrates the situation that the forward direction bus interface of expansion module and backward bus interface all do not insert cable, in this second case, when backward bus interface due to this expansion module inserts cable, then support normally closed switch K1 and make it disconnect, therefore in this case, terminal resistance R1 is disconnected with expansion bus and is connected.
As shown in Figure 3, then the connection diagram of the terminal resistance in a third situation of expansion module in the embodiment of the present invention is shown; The forward direction bus interface that it illustrates expansion module inserts cable, and backward bus interface does not all insert the situation of cable, in this second case, when backward bus interface due to this expansion module does not insert cable, normally closed switch K1 is in closure state, therefore in this case, terminal resistance R1 is still interconnected with expansion bus.
As can be seen from above, before PLC is connected with expansion module at different levels, expansion module at different levels is in the situation of Fig. 2; When PLC is connected with expansion module at different levels, then the expansion module being in front end is in the situation of Fig. 3, and because its backward bus interface all inserts cable, then the terminal resistance R1 in each expansion module is disconnected with expansion bus and is connected; And the expansion module of afterbody is in the situation of Fig. 4, because its normally closed switch K1 is in closure state, terminal resistance R1 is still interconnected with expansion bus, and namely terminal resistance has been automatically matched on expansion bus.
As shown in Figures 5 to 9, show in a specific embodiment, the structural representation that the backward bus interface of expansion module is connected with cable.Wherein, backward bus interface 4 is fixedly installed on expansion module 2 and (illustrate only the part on expansion module 2 in figure), and the cable be connected with backward bus interface 4 has a cable connector 5, particularly:
Backward bus interface 4 comprises: female body 40, and it is the framework of one end open, is provided with the multiple terminals 41 penetrating this body in it, is provided with a normally closed switch 42(i.e. K1 above between the plurality of terminal); This female body 40 sidewall draws the buckle 44 being used for being connected with cable connector 5 phase buckle.A sidewall of this female body 40 arranges a locating slot 43;
Cable connector 5 comprises: male body 50, and one end is provided with multiple terminal hole 51, is provided with a normally closed switch hole 52 between terminal hole 51, and a sidewall of this male body 50 is provided with locating piece 53.
Correspondingly, when this cable connector 5 matches with backward bus interface 4, the male body 50 of cable connector 5 holds in the female body 40 of backward bus interface 4, in terminal 41 insertion end sub-aperture 51, normally closed switch 42 inserts in normally closed switch hole 52, by the effect compressed, this normally closed switch 42 is opened, and buckle 44 blocks the end of male body 50, locating piece 53 is connected in locating slot 43, thus backward bus interface 4 and cable connector 5 are fixedly connected.
Correspondingly, as shown in Figure 10, the main flow schematic diagram of an embodiment of the terminal resistance automatic matching method of a kind of PLC expansion bus provided by the invention is shown.In this embodiment, the terminal resistance automatic matching method of this PLC expansion bus, be applied to PLC and multiple expansion module and have in the PLC control system of bus topolopy by expansion bus cascade, the method comprises the steps:
PLC is connected by order of cables with multiple expansion module;
In bus topolopy, when the forward direction bus interface and backward bus interface of expansion module at the corresponding levels are all inserted into cable, then the upper normally closed switch of expansion module is opened, and terminal resistance and the expansion bus of expansion module at the corresponding levels disconnect;
In bus topolopy on afterbody expansion module, its backward bus interface is not inserted into cable, the normally closed switch of last expansion module is in closure state, then the terminal resistance in afterbody expansion module is connected with expansion bus, and Auto-matching is on expansion bus.
More details, in the lump referring to figs. 1 to the explanation of Figure 10, can not repeat at this.
Implement the embodiment of the present invention, there is following beneficial effect:
The technical scheme that the embodiment of the present invention provides, all arrange a normally closed switch, and terminal resistance is connected on expansion bus by this normally closed switch by rear in each expansion module of the PLC system by expansion bus cascade in bus interface; When after each expansion module cascade, the expansion module mediated, because its backward bus interface is inserted into cable, makes the normally closed switch of its correspondence disconnect, thus the terminal resistance on expansion module at the corresponding levels and expansion bus is disconnected; And for last expansion module, because its backward bus interface is not inserted into cable, therefore the normally closed switch of its correspondence is in closure state, therefore can by terminal resistance Auto-matching to expansion bus.In the program, can rapidly and accurately by terminal resistance Auto-matching on expansion bus.
Above disclosedly be only present pre-ferred embodiments, certainly can not limit the interest field of the present invention with this, therefore according to the equivalent variations that the claims in the present invention are done, still belong to the scope that the present invention is contained.
Claims (6)
1. a terminal resistance automatic patching system for PLC expansion bus, it comprises PLC and multiple expansion module, and described PLC and described multiple expansion module form bus topolopy by expansion bus cascade, it is characterized in that, wherein:
Each expansion module all has a forward direction bus interface and a backward bus interface, is provided with normally closed switch in the rear in bus interface, and described normally closed switch connects a terminal resistance to described expansion bus;
When described backward bus interface inserts cable, then support described normally closed switch and make it disconnect.
2. the terminal resistance automatic patching system of a kind of PLC expansion bus as claimed in claim 1, is characterized in that, described expansion bus is MLVDS bus.
3. the terminal resistance automatic patching system of a kind of PLC expansion bus as claimed in claim 1 or 2, is characterized in that, the backward bus interface of each expansion module described comprises:
Female body (40), it is the framework of one end open, be provided with the multiple terminals (41) penetrating this body in it, be provided with a normally closed switch (42) between described multiple terminal (41), the sidewall of described female body (40) leads to buckle (44);
A sidewall of described female body (40) is provided with a locating slot (43).
4. the terminal resistance automatic patching system of a kind of PLC expansion bus as claimed in claim 3, is characterized in that, the cable be connected with described backward bus interface has a cable connector (5), and it comprises:
Male body (50), one end is provided with multiple terminal hole (51), between terminal hole (51), be provided with a normally closed switch hole (52), a sidewall of described male body (50) be provided with one with the locating piece (53) matched with described locating slot (43).
5. a terminal resistance automatic matching method for PLC expansion bus, be applied in the terminal resistance automatic patching system of the PLC expansion bus as described in any one of claims 1 to 3, it is characterized in that, the method comprises the steps:
PLC is connected by order of cables with multiple expansion module;
In bus topolopy, when being all inserted into cable in the backward bus interface of expansion module at the corresponding levels, then the upper normally closed switch of described expansion module is opened, and terminal resistance and the expansion bus of described expansion module at the corresponding levels disconnect;
In bus topolopy on afterbody expansion module, its backward bus interface is not inserted into cable, the normally closed switch of last expansion module described is in closure state, then the terminal resistance in afterbody expansion module is connected with expansion bus, on Auto-matching to described expansion bus.
6. the terminal resistance automatic matching method of a kind of PLC expansion bus as claimed in claim 5, is characterized in that, described expansion bus is MLVDS bus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510619901.3A CN105320056B (en) | 2015-09-25 | 2015-09-25 | The terminal resistance automatic patching system and method for a kind of PLC expansion bus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510619901.3A CN105320056B (en) | 2015-09-25 | 2015-09-25 | The terminal resistance automatic patching system and method for a kind of PLC expansion bus |
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| Publication Number | Publication Date |
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| CN105320056A true CN105320056A (en) | 2016-02-10 |
| CN105320056B CN105320056B (en) | 2018-07-03 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040117431A1 (en) * | 2002-10-24 | 2004-06-17 | Sun Microsystems, Inc. | Mapping of hot-swap states to plug-in unit states |
| CN103180797A (en) * | 2012-09-26 | 2013-06-26 | 华为技术有限公司 | Server system and external-card expansion device thereof |
| CN203799198U (en) * | 2014-02-24 | 2014-08-27 | 上海汽车集团股份有限公司 | Control module enabling CAN terminal resistor to be intelligently accessed |
| CN203984448U (en) * | 2013-12-30 | 2014-12-03 | 中通客车控股股份有限公司 | A kind of CAN bus module of tape terminal resistance selection circuit |
| CN204576183U (en) * | 2015-05-22 | 2015-08-19 | 东风汽车股份有限公司 | Multi-purpose CAN bus terminal resistor access device |
-
2015
- 2015-09-25 CN CN201510619901.3A patent/CN105320056B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040117431A1 (en) * | 2002-10-24 | 2004-06-17 | Sun Microsystems, Inc. | Mapping of hot-swap states to plug-in unit states |
| CN103180797A (en) * | 2012-09-26 | 2013-06-26 | 华为技术有限公司 | Server system and external-card expansion device thereof |
| CN203984448U (en) * | 2013-12-30 | 2014-12-03 | 中通客车控股股份有限公司 | A kind of CAN bus module of tape terminal resistance selection circuit |
| CN203799198U (en) * | 2014-02-24 | 2014-08-27 | 上海汽车集团股份有限公司 | Control module enabling CAN terminal resistor to be intelligently accessed |
| CN204576183U (en) * | 2015-05-22 | 2015-08-19 | 东风汽车股份有限公司 | Multi-purpose CAN bus terminal resistor access device |
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| CN105320056B (en) | 2018-07-03 |
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