Method for checking at least one first clock generator of a first field device in a process measuring system

1 . A method for checking a first clock signal generator of a first field device in a process measuring system, wherein the process measuring system includes the first field device and at least two other field devices having, in each case, a clock signal generator, wherein the first field device and the at least two other field devices each determines and/or monitors at least one chemical and/or physical parameter of a medium, wherein a desired frequency is predetermined for each clock signal generator and each clock signal generator produces an actual frequency, wherein the first field device is embodied to exchange information with the at least two other field devices, the method comprising:

producing the actual frequency of the first clock signal generator;

transmitting the produced actual frequency and the desired frequency of the first clock signal generator to the at least two other field devices;

ascertaining deviations of the actual frequency from the desired frequency of the first clock signal generator via the clock signal generators of the at least two other field devices;

transmitting the ascertained deviations to the first field device;

comparing the ascertained deviations and/or an average value of the ascertained deviations with a predetermined tolerance range of the desired frequency of the first clock signal generator; and

outputting at least one piece of state information concerning the first clock signal generator based on the comparison.

2 . The method as claimed in claim 1 ,

wherein a warning is output as the at least one piece of state information concerning the at least first clock signal generator, when the ascertained deviations and/or the average value of the ascertained deviations lie outside of the predetermined tolerance range of the desired frequency.

3 . The method as claimed in claim 1 , further comprising:

outputting a correction factor as the at least one piece of state information concerning the first clock signal generator, wherein the correction factor gives a degree with which the first clock signal generator differs from the predetermined tolerance range.

4 . The method as claimed in claim 3 , further comprising:

correcting the actual frequency of the first clock signal generator to the desired frequency with the help of the ascertained deviations and/or the average value of the ascertained deviations and/or the correction factor.

5 . The method as claimed in claim 1 , further comprising:

outputting as the at least one piece of state information concerning the first clock signal generator a remaining function length of time of the first clock signal generator after an expiration of which the ascertained deviations and/or the average value of the ascertained deviations will lie outside of the predetermined tolerance range.

6 . The method as claimed in claim 1 ,

wherein the first field device determines and/or monitors at least one chemical and/or physical parameter of the medium at least via the first clock signal generator.

7 . The method as claimed in claim 1 , further comprising:

weighting each ascertained deviation as a function of the field device by which it was ascertained.

8 . The method as claimed in claim 1 ,

weighting each ascertained deviation as a function of a piece of state information of the field device by which it was ascertained.

9 . The method as claimed in claim 8 ,

wherein used as state information of the field device are/is a time period since last calibration of the clock signal generator of the field device and/or the presence of a failure and/or a need for maintaining the field device and/or an accuracy class of the at least one clock signal generator of the field device.

10 . The method as claimed in claim 1 ,

wherein an accuracy class of the first clock signal generator is used as the predetermined tolerance range of the at least first clock signal generator.

11 . The method as claimed in claim 1 ,

wherein the first field device is a density measuring device, a flow measuring device, or a travel time fill level measuring device.

12 . A method for checking a first clock signal generator of a first field device in a process measuring system, wherein the process measuring system includes the first field device and at least two other field devices having, in each case, at least one clock signal generator, wherein the first field device and the at least two other field devices each determines and/or monitors at least one chemical and/or physical parameter of a medium, wherein a desired frequency is predetermined for each clock signal generator and each clock signal generator produces an actual frequency, wherein the first field device is embodied to exchange information with the at least two other field devices, the method comprising:

producing an actual frequency of the first clock signal generator;

transmitting the produced actual frequency of the first clock signal generator to the at least two other field devices;

checking the actual frequency of the first clock signal generator via the clock signal generators of the at least two other field devices;

determining reference frequencies of the first clock signal generator as a result of checking the actual frequency of the first clock signal generator;

transmitting the reference frequencies to the first field device;

ascertaining deviations of the reference frequencies from the desired frequency of the first clock signal generator,

comparing the ascertained deviations and/or an average value of the ascertained deviations with a predetermined tolerance range of the desired frequency of the first clock signal generator; and

outputting at least one piece of state information concerning the at least first clock signal generator based on the comparison.