GB2271491A

GB2271491A - Control arrangement for valves via a bus line

Info

Publication number: GB2271491A
Application number: GB9319596A
Authority: GB
Inventors: Peter Saffe; Georg Geier; Hans F Meyer; Huu-Tri Nguyen
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1992-09-22
Filing date: 1993-09-22
Publication date: 1994-04-13
Anticipated expiration: 2013-09-22
Also published as: FR2695977A1; GB2271491B; DE4232518A1; FR2695977B1; ITMI932028A0; GB9319596D0; IT1272660B; DE4232518C2; ITMI932028A1

Abstract

A control arrangement for valves (1, 2,...n) and/or valve units includes a central electronic control (SPS) (30) with a bus line (40) at the output thereof by way of which at least one coded control signal can be transmitted and serves for the addressed valve control. A bus system having serial data transmission is used and the valves (1, 2,...n) are connected in parallel by way of the bus line (40). Each valve is provided with a separate decoding element (10) at the valve location. A large number of valves may thus be coupled to a joint bus line and may be controlled by way of the same. A protocol converter (20), Fig. 2 (not shown), allows programming of elements (10) of the individual valves. <IMAGE>

Description

2271491 A CONTROL ARRANGEMENT FOR VALVES AND/OR VALVE UNITS The invention

relates to a control arrangement f or valves and/or valve units, and in particular, to such a control arrangement with a central electronic control (SPS), having a bus line at the output thereof, by which at least one coded control signal can be transmitted and serves for the addressed valve control.

Control arrangements f or valves and/or valve units with bus control are known, for example, from the brochure data sheet 13.055, September 1991 of Mannesmann Rextroth Pneumatik. In this respect, provision is made for combining a valve arrangement into a valve unit and for then providing such a subassembly unit with an electronic system with is centrally arranged with respect to the subassembly and which inter alia decodes the bus signals and determines therefrom the control of the individual valves. Electrical leads extend from the output of the decoding electronic system to the actuating magnets of the individual valves.

However, in practice, it has been found that in some instances valve units consist of many valves whilst in other instances they consist of only a few valves. By valve unit is meant, in this respect, an arrangement of several individual valves combined into a subassembly. It is, therefore, known in the prior art to design such valve unit central electronic decoding systems in such a way that they can be used with up to a specific number of individual valves. The result of this is that in the case of valve units having few valves the central electronic decoding system is oversized. For valve units having multiple individual valves, this type of construction does indeed again become more economical, but the disadvantage then arises that there is a preset upper limit to the number of valves.

An object of the invention, therefore, is to provide a control arrangement such that any number of valves can be economically controlled.

A control arrangement for valves and/or valve units, 2 in accordance with the invention, comprises a central electronic control (SPS) having a bus line at the output thereof by which at least one coded control signal can be transmitted and serves for the addressed valve control wherein a bus system having serial data transmission is provided, the valves being connected in parallel by way of the bus line and wherein each valve is provided with a decoding component at the valve location.

Thus, the advantage is achieved that a virtually unlimited number of individual valves can be combined into one valve subassembly or valve unit.

The combination is effected, in this respect,--purely by way of the central electronic control or the central computer. This means that it is thus possible even to combine individual valves into valve units only in or through the central computer. An advantage of this is that the valve units can be changed at will, i.e. can be assembled anew. Thus, the necessary decoding electronic system arranged at the valve unit centrally with respect to the individual valves of known arrangements can be dispensed with. Therefore, the size of the valve unit is no longer dependent upon the number of electrical inputs and outputs of the central decoding electronic system. In the known arrangements use of a central valve-unit decoding electronic system meant that individual lines had to be connected from the output to each individual valve. This expensive measure in avoided in the case of the proposed arrangement also, since the bus line is looped through from one valve to the next.

In a further development the decoding element is integrated into the valve housing or the decoding element is integrated in a plug associated with the respective valve. As the decoding element is reduced to the necessary functions only, the element is correspondingly small and thus structurally also integratable. Use of a protocol converter within the bus line allows coding of each individual decoding element and thus each individual valve.

3 If the protocol converter is dispensed with, it is then necessary to program or to code the individual valves by plugging onto a manual programming unit. Through the use of a decoding element with a nonvolatile memory component (EEPROM) it is, moreover, possible to introduce into the decoding element, besides the address coding, also a parametering. Thus, the decoding of the address and parametering is possible at each individual valve.

By 11parametering11 is meant the storage of corresponding process parameters for control of the valve. For example, it includes the time and the flank through which the valve is to be controlled. With appropriate parametering initially only one "control pulse" by way of the bus line may be necessary. The valve, after accepting the appropriately addressed signal, automatically and without access to an external data line runs through a previously stored actuation course.

If these significant advantages are considered in conjunction with the fact that the valve units can be individually assembled and changed or extended, then the result is that such an extension can be undertaken without programming of a valve-unit central electronic system which is otherwise customary in the prior art. The advantages of such a decentralisation of coding and parametering include not only userfriendliness but also the rapidity of such a control arrangement.

The invention will now be further described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic drawing of a control arrangement with direct control of the valves from an SPS; and Figure 2 illustrates use of a protocol converter.

Figure 1 shows schematically control of a number of valves designated 1, 2,...n. This representation and 4 designation of the last valve with n is intended to illustrate that the number of controllable valves is, in principle, not restricted.

From a central unit 30 (SPS) there extends a bus line 40, which is conducted continuously from one valve to the next. Each valve consists substantially of a valve body 12, which is provided with the pressure connections and comprises a switching valve member, an actuating magnet 11 which actuates the valve member, and a decoding module 10.

It is possible, by way of the SPS 30, for division of the 1 to n valves into individual valve groups or- valve units to be undertaken in the SPS 30 by programming. A central electronic valve-unit-control system for the decoding of the control signal conducted by way of the bus line 40 may be eliminated with the proposed arrangement. An effectively unlimited number of valves can be attached to the bus line 40, as each valve has a decoding module or element 10 associated with it and arranged in the region of the valve itself. It is, of course, possible to build up a certain number of valves structurally on a base plate, whereby electrical and pressure-medium lines can be conducted in integrated manner to the respective valves. The controlwise or administrative division into valve groups is effected, in this respect, centrally by way of the SPS 30. This means that basically the arrangement of a central electronic decoding system on each valve unit can be dispensed with. Thus, it is also possible to combine, for example, valves which are isolated on a large installation and which are not arranged jointly on a base plate by way of the computer into an "imaginary" valve unit. Such an "imaginary" valve unit formation may have considerable application advantages. As already mentioned above, a constructional advantage manifests itself here in the design of the schematically represented bus line 40. This can be continuous with- a lead connected to each individual valve. This means that there are no control lines running in a star-shaped manner from a junction to the individual valves, but rather the bus line is led through (looped through) from one valve to the next.

Figure 2 shows an embodiment in which programmability of the control addresses of the individual decoding elements 10 is possible. A protocol converter 20 is joined up the bus line 40, which leads to the individual valves 1, 2,...n, and connected by way of the bus line 41 to the SPS 30. The protocol converter 20 is controlled from the SPS 30 by way of the bus line 41 and this is controlled by way of a switch-on card 31, which is integrated in the SPS 30. The protocol converter 20 allows programming of the decoding elements 10 of the individual valves. In this respect substantially the address code is programmed, so that each individual valve-related decoding module 10 knows the address code to cause it to accept a future control signal. The protocol converter 20 serves, moreover, for connecting two different bus systems to one another. For this reason the bus line is subdivided into a section 40 and 41, the subdivision being intended to make it clear that the protocol converter connects these two bus systems to one another.

For the programming of the addresses the protocol converter 20 is switched into a programming mode. A desired address is imputed by way of a keyboard present at the converter 20. This is then sent together with a code cyclically onto the bus. The desired valve or the corresponding decoding element 10 is then addressed by pressing a key present at the protocol converter 20. Equally the programming of the addresses with the aid of a manual programming unit is possible. The programming unit is either connected to the bus or directly to the bus connection of the individual valve or decoding element 10.

In a special development, the decoding element can additionally contain a non-volatile memory component (EEPROM). As this results in a further store being contained in the decoding element, as well as the actual 6 address coding, parametering can be introduced. By parametering is meant certain control parameters which can also be stored in the memory. It will be understood that after corresponding decoding of the address, and thus acceptance of a control signal, the memory then additionally cointroduces corresponding valve-specific parameters such as control flank, control speed, switching speed, holding time and so forth, with which the actuating magnet 11 of the valve is then actuated. That is to say, the information as to what a valve has to do and for how long after actuation of the valve, is deposited at the location of the individual valve. This means that an entire process course may be stored away decentrally at the location of each individual execution member, in this case, valves. This then leads to the fact that the entire installation can work extremely rapidly, since the parametering no longer has to run by way of the bus line from the SPS 30 or by way of.the protocol converter 20. The use of such "intelligent" valves makes the forming of valve subassemblies, for example valve units, very elegant. Furthermore such decoding elements when formed as userspecific integrated circuits are nothing more than microcomputers reduced in terms of circuitry to the minimum necessary for the functions involved. This reduction to the minimum required produces faster switching times than with standard microcomputers. Furthermore, such a structural minimising of the decoding elements has the consequence that they can be produced extremely economically and in large numbers. It has been found that, with use of the proposed arrangement, the provision of one decoding element per valve is still more economical than the provision of one central electronic decoding system per valve unit can be. Above all, however, the structural minimisation is a considerable advantage. A further advantage is that the "decoding electronic system" in the manner of the proposal is never oversized or undersized and that valve units can be assembled from a virtually 7 limitless number of valves.

The use of buscontrollable valves and valve units can thus appropriately be designated as a system of I'decentral intelligence". This has the advantage of extremely short switching and reaction times, which will be particularly pertinent in the case of large pneumatically controlled installations.

8

Claims

1. A control arrangement f or valves and/or valve units comprising a central electronic control (SPS) having a bus line at the output thereof by which at least one coded control signal can be transmitted and serves for the addressed valve control wherein a bus system having serial data transmission is provided, the valves being connected in parallel by way of the bus line and wherein each valve is provided with a decoding component at the valve location.

2. A control arrangement as claimed in Claim 1, including a central protocol converter connected into the bus line for coding each decoding element.

3. A control device as claimed in either Claim 1 or 2, wherein each decoding element has a non-volatile memory component.

4. A control arrangement as claimed in any preceding Claim, wherein each decoding element is integrated in the housing of the associated valve._

5. A control arrangement as claimed in any one of Claims 1 to 3, wherein each decoding component is integrated in a plug body of the associated valve.

6. A control arrangement as claimed in any preceding claim for a valve unit comprising modular base-plate elements and plug-on valves, the base-plate elements being provided with integrated electrical plug-in elements for connection of the bus line and/or of a supply line.

7. A control arrangement substantially as herein described and illustrated in the accompanying drawings.