Overview - Siemens SIMATIC S7-200 System Manual

S7-200 Programmable Controller System Manual

Overview

Support for data logs have been incorporated into STEP 7--Micro/WIN and the S7-200 PLC. With
this feature, you can permanently store records containing process data under program control.
These records can optionally contain a time and date stamp. You can configure up to four
independent data logs. The data log record format is defined using the new Data Log Wizard
All data logs are stored in the memory cartridge. To use the data log feature, you must have
installed an optional 64K or 256K memory cartridge in your PLC. See Appendix A for information
about the memory cartridges.
You must use the S7-200 Explorer to upload the contents of your data logs to your computer.
An example of a Data Log application is shown in Figure 14-1.
Memory Cartridge
S7-200 CPU
TD 200C
Figure 14-1 Example of Data Log Application
Data Log Definition and Terminology
To help you understand the Data Log Wizard, the following definitions and terms are explained.
A data log is a set of records usually ordered by date and time. Each record represents
-
some process event that records a set of process data. The organization of this data is
defined with the data log wizard.
A data log record is a single row of data written to the data log.
-
374
Data Log: "Grain Bin Capacity"
Data Log: "Morning Milking"
03/22/2004 05:25:04 4 27.7
03/22/2004 05:21:04 7 30.8
03/22/2004 05:17:04 2 25.1
.
.
.
Write Data Log Record
(with date and time stamp added)
5, 35.2, 98.1, 14.5
Morning milking data buffer
in V memory
Cow #5 Milking Complete
97.5 13.2
97.3 12.7
97.6 14.1
Upload Data
Log Daily
For this cow:
H
H
H
H
S7-200 Explorer
Cow #5
Record unique ID
Record amount of
milk obtained
Record cow
temperature
Record milking time