Functions; Principle Of Operation - Siemens SIMATIC S5 Manual

4

Functions

Principle of Operation

4.1
The module is operated by means of commands and instructions, regardless of whether they are
sent to the IP247 by the CPU or by a programmer. Commands are divided into two basic groups:
instructions for "operating" and
commands for "monitoring".
Operating instructions are used for the following:
to setup an axis (input of machine data),
to set (change) modes,
to start the execution of a mode,
to abort the execution of a mode
The reaction to an operating instruction depends on various factors.
The instruction must be feasible.
It must be feasible in the currently set mode and during execution of the mode.
It must not contradict the "axis attributes" which determine whether or not an operating
mode is permissible at a given time (=> Section 2.7 "Axis Attributes").
It must not contradict the mode of the other axes, if they have already been set by pre-
vious operating instructions (e.g. "teach-in" or "delete program").
If all these conditions are fulfilled, the operating instruction will be processed, otherwise an error
message is output and with a few exceptions processing is terminated.
oldest valid job in this list. If the job is permitted in the current axis status, it is executed immedi-
ately. If it contradicts the current mode, the mode is terminated and an error message output.
Note
An operating instruction which causes a mode to start should only be transferred to
the module when the previous job is complete.
While an axis is braking, further jobs are accepted, however, not interpreted since they would
trigger a stop and the module is already braking. If several jobs are sent to the IP247 during this
phase, it is possible that an entry cannot be made in the job list. These jobs are then lost. The
Principle of Operation
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