Siemens SIMATIC S7-300 Manual page 204

Description of Functions
Table 9-7 Control actions for "MDI" mode (examples), continued
Signal name
Control action 3, stop during positioning with new start signal for resumed positioning
Control signal:
Stop [STP]
Checkback signals:
Travel minus [FR–]
Start enable [SFG]
Control signal:
Start [ST]
Checkback signals:
Travel minus [FR–]
Start enable [SFG]
Control action 4, stop during positioning with new start signal and new MDI block
Control signal:
Stop [STP]
Checkback signals:
Travel plus [FR+]
Start enable [SFG]
Transfer MDI block (job no.
6)
Transfer "delete residual
path" (job no. 11)
Control signal:
Start [ST]
Checkback signals:
Travel minus [FR–]
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Level
If Stop is enabled during positioning, the axis stops. [FR–] is
reset, and [SFG] is activated. [BL] remains active and [PEH]
is not output, since positioning is not complete
If [ST] is initiated again, [FR–] and [SFG] are reset and posi-
tioning is completed.
Before the axis comes to a standstill, it is possible to define a
new direction "through start".
If Stop is enabled during positioning, the axis stops. [FR+] is
reset, and [SFG] is activated.
When a new MDI block has been transferred, [ST] is enabled
again. "Delete residual path" is also enabled.
The axis deletes the residual path of the old positioning op-
eration, and starts executing the new traversing block.
[FR–] is enabled, and [SFG] is reset.
Note:
If no new "MDI block" is transferred, execution of the cur-
rent "MDI block" is repeated from the start.
Without "delete residual path", the interrupted positioning
operation would be continued (see control action 3)
Explanation
.
FM 354 Servo Drive Positioning Module