Siemens S7-400PLC Specifikace stáhnout pdf (Strana 462)

Glossary

S7-400 Automation System Module Data

462 Reference Manual, Edition 09/2009, A5E00850736-06

these modules, you should make sure that the measurement signal is "clean", for example

by adhering to the installation instructions.

Measuring principle, integrating

A module with an integrating measurement technique is always used for measurements that

are not time-critical. The integration time is inversely proportional to the network frequency.

You set the network frequency in STEP 7 and this results in the integration time. At a

network frequency of 50 Hz, the integration time is 20 ms or even multiples of 20 ms. Since

the measured value is integrated over exactly this period, at least one or more entire periods

of the network frequency that may be superimposed on the measurement signal are also

recorded. The mean value of the interference is therefore integrated to zero (positive

component of the first half period = negative component of the second half period) and, as a

result of the principle, only the useful signal is detected.

Measuring range module

Measuring range submodules are plugged onto analog input modules to adapt them to

various measuring ranges.

Memory reset

During a memory reset, the following memory areas of the CPU are erased: Work memory,

write/read area of the load memory, system memory.

The MPI parameters and the diagnostic buffer are retained.

Mode

Mode means the following:

1. The mode in which the CPU operates as set by the mode selector or using a PG

2. The type of program execution on the CPU

Mode selector

Using the mode selector, the user can set the current mode of the CPU (RUN, STOP) or

reset the memory of the CPU (MRES).

Noise suppression

Parameter in STEP 7 for analog input modules. The frequency of the alternating voltage

power supply can interfere with the measured value, in particular when measuring small

voltage ranges and with thermoelements. With this parameter, the user specifies the

predominant power supply frequency in the system.

Non-isolated

With non-floating input/output modules, the reference potentials of the control and load

circuits are electrically interconnected.

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Siemens S7-400PLC Specifikace Strana 462