Method for maintaining the functional ability of a field device

Abstract

A method for maintaining the functional ability of a field device of automation technology, wherein the method comprises the following steps: monitoring the field device for at least one achieved parameter change (Δn.sub.x), wherein the parameter change (Δn.sub.x) converts an old parameter set (n.sub.x-1) into a new parameter set (n.sub.x), storing all parameter changes (Δn.sub.x) achieved in the field device in a parameter change history, monitoring the field device for an occurring malfunction (F); and, performing a remediation measure, wherein the parameter change history and/or a parameter to malfunction, linking element is accessed for remediating the malfunction occurring in the field device.

Claims

1. A method for maintaining the functional ability of a field device of automation technology, comprising the steps of: monitoring the field device for at least one achieved parameter change (Δn.sub.x); wherein the parameter change (Δn.sub.x) converts an old parameter set (n.sub.x31 1) into a new parameter set (n.sub.x); storing all parameter changes (Δn.sub.x) achieved in the field device in a parameter change history (PH); monitoring the field device for an occurring malfunction (F); and performing a remediation measure (RM), wherein the parameter change history (PH) and/or a parameter to malfunction, linking element (LE) is accessed for remediating the malfunction occurring in the field device (F), wherein: at least one of the following alternative method steps is executed for performing said remediation measure (RM); revoking the parameter change (Δn′.sub.x) last performed before the occurring malfunction (F), wherein the last performed parameter change (Δn′x) is ascertained by means of the parameter change history (PH); revoking at least one operator selected parameter change (Δn″.sub.x), wherein available to an operator (O) for selection are all parameter changes (Δn″.sub.x) performed in the field device and stored in the parameter change history (PH) and in the case of ΔΔTA selection by the operator (O) the field device revokes such operator selected, parameter change (Δn″x); and revoking at least one automatically ascertained parameter change (Δn′″x), wherein for ascertaining the at least one automatically ascertained parameter change (Δ′″.sub.x) the parameter to malfunction, linking element (LE) is accessed and wherein offered to the operator (O) for selection is this at least one automatically ascertained parameter change (Δn′″.sub.x) and in the case of selection by the operator (O) the field device revokes such at least one automatically ascertained parameter change (Δn′″x).

2. The method as claimed in claim 1, wherein: all achieved parameter changes (Δn.sub.x) are stored in such a manner in the parameter change history (PH) that the old parameter set (n.sub.n−1), which existed before the respectively achieved parameter change (Δn.sub.x) was made, can be brought back.

3. The method as claimed in claim 1, wherein: for ascertaining an automatically ascertained parameter change (Δn′″.sub.x) at least one of the following method steps is executed: accessing the parameter to malfunction, linking element (LE), wherein the parameter to malfunction, linking element (LE) includes at least one known malfunction (F.sub.a), which is linked with at least one known parameter change (Δn.sub.a); comparing the occurring malfunction (F) with all known malfunctions (F.sub.a) furnished in the parameter to malfunction, linking element (LE), wherein in the case of an agreement of the occurring malfunction (F) with one of the furnished known malfunctions (F.sub.a), the known parameter change (Δn.sub.a) linked to the agreeing furnished known malfunction (Fa) is selected; comparing the selected known parameter change (DELTA n.sub.a) with all parameter changes (Δn.sub.x) performed and stored in the field device, wherein in the case of an agreement of the linked known parameter change (Δn.sub.a) with a parameter change (Δn.sub.x) performed and stored in the field device, such is offered to the operator (O) as automatically ascertained parameter change (Δ″″x) for revocation.

4. The method as claimed in claim 1, wherein: known malfunctions (F.sub.a) furnished in the parameter to malfunction, linking element (LE) are linked with the known parameter changes (Δn.sub.a) based on statistical data and/or empirical values and/or already performed remediation measures (RM).

5. The method as claimed in claim 1, wherein: said remediation measure to be performed (RM) is selected by the operator (O) via a remediation measures list (RL).

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention will now be explained in greater detail based on the appended drawing, the sole figure of which shows as follows:

(2) FIG. 1 shows schematically, essential elements of the method of the invention.

DETAILED DISCUSSION IN CONJUNCTION WITH THE DRAWINGS

(3) FIG. 1 shows essential elements for performing the method of the invention for maintaining the functional ability of a field device of automation technology. To this end, possible events are shown schematically on a time axis TA. Time axis TA serves, in such case, for simpler description, respectively representation, of possible events, which can occur for a field device, especially parameter changes Δn.sub.x, respectively configuration changes and malfunctions occurring in the field device F. The field device has, in such case, a parameter set corresponding to the delivery state n.sub.0. Starting with this parameter set n.sub.0, then possible parameter changes Δn.sub.x are carried out in the field device. In such case, especially parameter changes Δn.sub.x are meant, which are performed after delivery of the field device.

(4) Further shown in FIG. 1 are the parameter changes Δn.sub.1-Δn.sub.x performed in the field device, in which case the old parameter set is designated generally with n.sub.x-1 and the new parameter set (which results from the old parameter set and the performed parameter change Δn.sub.x) generally with n.sub.x.

(5) The method of the invention aims, in such case, to achieve the goal that a field device, which has experienced a user initiated parameter change Δn.sub.x, respectively configuration change, and, thereafter, over the course of its product life, a malfunction F resulting therefrom, is able to perform a remediation measure RM, in order so to maintain its functional ability. For this, the method provides that the field device or the operating, or servicing, tool accesses a parameter change history PH and/or a parameter to malfunction, linking element LE, in order with the assistance of one of these or a combination of both of these to ascertain and to perform a remediation measure RM suitable for remediating the occurring malfunction F.

(6) The method provides for its performance that the field device retains in a parameter change history PH parameter changes Δn.sub.x performed during its product life. The performed parameter changes Δn.sub.x are kept in the parameter change history PH in such a manner that they are uniquely arranged relative to one another as a function of time of occurrence and relative to arising malfunctions.

(7) A parameter change Δn.sub.x transforms an old parameter set n.sub.x-1 stored in the field device into a new parameter set n.sub.x, which is likewise stored in the field device and, thus, replaces the old parameter set n.sub.x-1. In such case, a parameter set n.sub.x can comprise both an individual parameter, as well as also a number of individual parameters. Furthermore, an option is that both an individual parameter as well as also a number of different parameters can be changed at a certain point in time.

(8) Parameter changes Δn.sub.x performed, respectively achieved, in the field device are, such as already described, kept in a parameter change history PH in a form such that the old parameter set n.sub.x-1, which was stored in the field device before the performed, respectively achieved, parameter change Δn.sub.x, can be reinstalled. For this, a number of variants are provided. For example, the entire parameter set n.sub.x-1, which existed before the parameter change Δn.sub.x was made, can be kept in the parameter change history PH in a form such that each individual parameter is furnished with its corresponding value.

(9) An alternative variant can be that in which not the entire parameter set n.sub.x-1 is kept in the parameter change history PH, but, instead, only the values, which have changed as a result of the performed parameter change Δn.sub.x. This variant offers, compared with the preceding variant, in the case of which the entire parameter set n.sub.x-1 is stored, the advantage that memory capacity can be saved and the individual parameter sets n.sub.x-1 can be derived by means of recursion.

(10) By way of example, the following table shows some entries for parameter changes Δn.sub.x illustrating how they can be stored in the parameter change history PH:

(11) TABLE-US-00001 parameter old value distance unit mm  4 mA value 100 20 mA value 400  4 mA value 200

(12) Additionally to monitoring for a parameter change Δn.sub.x, the field device is also monitored for an occurring malfunction F, in order, in the case of the occurrence of a malfunction F, to perform a remediation measure RM. This remediation measure RM, for remediating the occurring malfunction F, accesses either the parameter change history PH or a parameter to malfunction, linking element LE or both of these.

(13) The parameter to malfunction, linking element LE is a kind of lookup table, in which known malfunctions are listed. Additionally in the parameter to malfunction, linking element LE, known malfunctions F.sub.a are linked with known parameter changes Δn.sub.a, which can trigger these malfunctions. The known malfunctions F.sub.a furnished in the parameter to malfunction, linking element LE can be stored linked with the corresponding, known parameter changes Δn.sub.a based on statistical data and/or empirical values, for example, of the manufacturer or also of the operator O, and/or already performed remediation measures RM. In such case, it is also an option that a known malfunction F.sub.a appears a number of times in the lookup table and is linked with different known parameter changes Δn.sub.a, all of which can trigger the same malfunction F.sub.a.

(14) In the normal case, this table, respectively the parameter to malfunction, linking element LE, is coded persistently in the field device. However, in order to save memory capacity, an option is to store such information outside of the field device, for example, where the operating tool is located. Furthermore, the parameter to malfunction, linking element LE can be embodied as a dynamic table, which can be expanded, respectively adapted, corresponding to newest knowledge concerning the effect of a known parameter change Δn.sub.a on a known malfunction F.sub.a.

(15) The following table gives, by way of example, some entries illustrating storing, respectively furnishing, of data in a parameter to malfunction, linking element LE:

(16) TABLE-US-00002 malfunction parameter S441 electrical current output  4 mA value S441 electrical current output 20 mA value C207 simulation is active simulation mode

(17) As already indicated, for remediating an occurring malfunction F, a remediation measure RM is performed. In such case, the method provides three alternative steps as follows: i. Revoking the parameter changes Δn′.sub.x last performed before the occurring malfunction F. For this, the parameter change history PH is used to ascertain the parameter change Δn′.sub.x performed before the point in time of the occurrence of the malfunction F. Based on this parameter change Δn′.sub.x, then the parameter set n′.sub.x-1 is reproduced, which was made before the occurrence of the malfunction F; ii. Revoking at least one operator selected, parameter change Δn″.sub.x. Available to the operator O for selection are all parameter changes Δn.sub.x performed in the field device and stored in the parameter change history PH. After selection by the operator O, the operator selected, parameter change Δn″.sub.x is revoked. In this way, the operator O can decide whether or not a parameter change Δn.sub.x is responsible for the occurrence of the malfunction F; and iii. Revoking at least one parameter change Δn′″.sub.x ascertained automatically by the field device or the operating, or servicing, tool. For this, the parameter to malfunction, linking element LE is accessed in such a manner that the occurring malfunction F is compared with all already known malfunctions F.sub.a furnished in the parameter to malfunction, linking element LE. In the case of an agreement, the at least one known parameter change Δn.sub.a linked to this known malfunction F.sub.a is selected. As already described, the parameter to malfunction, linking element LE can also link a known malfunction F.sub.a with a number of different known parameter changes Δn.sub.a. Accordingly, the at least one selected known parameter change Δn.sub.a is offered to the operator O in a remediation measures list RL as automatically ascertained parameter change Δn′″.sub.x for revocation. The operator O can try revoking individual parameter changes Δn.sub.x, which have an influence on the occurring malfunction F. In the case of this variant, the parameter change history PH can be omitted, which is advantageous especially in the case of field devices with little memory capacity.

(18) An alternative variant for revocation of an automatically ascertained parameter change Δn′″.sub.x provides that the at least one known parameter change Δn.sub.a ascertained by means of the parameter to malfunction, linking element LE is supplementally compared with the parameter changes Δn.sub.x stored in the parameter change history PH and only in the case of additional agreement with one of the entries of the parameter change history PH is such offered to the operator O by means of a remediation measures list RL for revocation.