Siemens S7-1200 - Mc_Moverelative (Position Axis Relatively) Instruction

Technology instructions
9.3 Motion control
S7-1200 Programmable controller
466 System Manual, 03/2014, A5E02486680-AG
Override response
The MC_MoveAbsolute tas
k can be
aborted by the following motion control
tasks:
•
MC_Home Mode = 3
•
MC_Halt
•
MC_MoveAbsolute
•
MC_MoveRelative
•
MC_MoveVelocity
•
MC_MoveJog
The new MC_MoveAbsolute task aborts
the following active motion control tasks:
•
MC_Home Mode = 3
•
MC_Halt
•
MC_MoveAbsolute
•
MC_MoveRelative
•
MC_MoveVelocity
•
MC_MoveJog
9.3.5.7
MC_MoveRelative (Position axis relatively) instruction
Table 9- 39 MC_MoveRelative instruction
LAD / FBD
SCL
Description
"MC_MoveRelative_DB"(
Axis:=_multi_fb_in_,
Execute:=_bool_in_,
Distance:=_real_in_,
Velocity:=_real_in_,
Done=>_bool_out_,
Busy=>_bool_out_,
CommandAborted=>_bool_out_,
Error=>_bool_out_,
ErrorID=>_word_out_,
ErrorInfo=>_word_out_);
Use the MC_MoveRelative
instruction to start a positioning
motion relative to the start position.
In order to use the
MC_MoveRelative instruction, the
axis must first be enabled.
1
STEP 7 automatically creates the DB when you insert the instruction.
2
In the SCL example, "MC_MoveRelative_DB " is the name of the instance DB.
Table 9- 40 Parameters for the MC_MoveRelative instruction
Parameter and type
Data type
Description
Axis IN TO_Axis_1 Axis technology object
Execute
IN
Bool
Start of the task with a positive edge (Default value: False)
Distance IN Real Travel distance for the positioning operation (Default value: 0.0)
Limit values: -1.0e
12
≤ Distance ≤ 1.0e
12
Velocity IN Real Velocity of axis (Default value: 10.0)
This velocity is not always reached on account of the configured
acceleration and deceleration and the distance to be traveled.
Limit values: Start/stop velocity ≤ Velocity ≤ maximum velocity
Done
OUT
Bool
TRUE = Target position reached
Busy
OUT
Bool
TRUE = The task is being executed.