Siemens SIMATIC S7-300 Manual page 106

Glossary
STARTUP
STARTUP mode initiates the transition from STOP to RUN mode. STARTUP can be
triggered by setting the → mode selector, by power on, or by an operator action on the
programming device. S7-300 performs a → restart.
Substitution value
Values output by faulty signal output modules to the process, or used to substitute a process
value of a faulty signal input module in the user program.
Users can program the substitute values in STEP 7 (hold last value, substitution value 0 or
1.) Those values must be set at the outputs when the CPU goes into STOP.
System diagnostics
Denotes the detection, evaluation and reporting of error events within the automation
system. Examples of such errors are: program errors, or module failure. System errors may
be indicated by LED displays, or in
Temperature error
Denotes the drift of measured/output values, caused by fluctuation of the ambient
temperature at an analog module. It is defined in % per Kelvin, relative to the rated range of
the analog module.
Temperature error of internal compensation
Only applies to the measurement of thermocouples. Defines the error to add to the actual
temperature error, when "internal comparison" mode is selected. The error is defined either
as a percentile value relative to the physical rated range of the analog module, or as an
absolute value in °C.
Ungrounded
no galvanic connection to ground potential
User program
Contains statements, tags and data for processing signals which can control a plant or
process. It is assigned to a programmable module (CPU, FM, for example) and can be
organized in smaller units (blocks).
Wirebreak
Parameter in
encoder and input, or between the actuator and output. The module detects a wirebreak
based on a current flow at the appropriately programmed input/output.
106
STEP 7
STEP 7
. A wirebreak check is used to monitor line continuity between the
.
SM 335 - High-speed analog mixed module for SIMATIC S7-300
Manual, 02/2009, A5E02409063-01