Connections; Inputs - Siemens Simatic Manual

Fail-safe function blocks for storage and retrieval machines
3.6.2

Connections

All bool variables listed in the following tables are preassigned FALSE, all integer variables are preas-
signed 0 – and all word variables preassigned W#16#0.
3.6.2.1

Inputs

Name Data type
SAFE_POS Int
POS_VALID Bool
SAFE_V Int
V_VALID Bool
X_NEGATIVE Int
X_POSITIVE Int
V_MAX Int
VMAX_RELEASE Int
RELEASE Bool
ACK Bool
S7-Distributed Safety/SIMATIC Safety - fail-safe function blocks for storage and retrieval machines
Description
Safety actual position [SLU]
is supplied from the F_SAFE_POS block.
The machine is stopped if this value violates one of the limit
values X_POSITIVE or X_NEGATIVE.
Actual position valid
is supplied from the F_SAFE_POS block.
1: Position is plausible
0: Position is not plausible, e.g. the discrepancy between the
two encoders is outside the tolerance band.
Safe actual velocity [SLU/mm]
is supplied from the F_SAFE_POS block.
If the actual velocity is higher than the upper limit in operation
calculated by the block, or higher than the upper limit parame-
terized at VMAX_RELEASE in the retraction mode, then output
SLS_OK is reset and the machine is stopped.
Actual velocity valid
is supplied from the F_SAFE_POS block.
1: The velocity is plausible
0: The velocity is not plausible, e.g. the increase of the devia-
tion between the two encoders over time is outside the toler-
ance band
Min. permissible position [SLU]
If the value at input SAFE_POS falls below this limit value, then
output X_NEGATIVE_OK is reset.
Max. permissible position [SLU]
If the value at input SAFE_POS X exceeds this limit value, then
output X_POSITIVE_OK is reset.
Maximum permissible velocity [SLU/mm]
Also see the diagram under Point 7 in Chapter 3.6.3
Retraction velocity [SLU/min]
If the block is in the retraction mode, then this value is output at
SLS_THRESHOLD.
VMAX_RELEASE must be parameterized in the range 1 <=
VMAX_RELEASE <= V_MAX.
Retracting
If the permitted position range was exited, then after a positive
edge at this input, the axis can be traversed back into the per-
missible position range with the velocity parameterized at
VMAX_RELEASE. While retracting, motion is immediately
stopped if a 0 signal is present at this input.
Acknowledging
If a fault occurs in normal operation, then this must be reset
using ACK before the system can be restarted.
The acknowledgment is only realized with a positive edge at
ACK, and has no effect in normal operation.
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