Siemens simatic et 200s Operating Instructions Manual page 326

1PosUniversal/Digital
7.6 Functions of the 1PosU
Parameters
Drive
Control mode
T direction change
min
Effect of the Hardware Limit Switches
The two digital inputs (DI0 and DI1) are evaluated by the 1PosU as limit switches:
● DI0 is the minus limit switch and limits the operating range in the minus direction.
● DI1 is the plus limit switch and limits the operating range in the plus direction.
You can assign parameters to the hardware limit switches separately as break contacts or
make contacts.
The hardware limit switches are evaluated with linear axes and rotary axes.
Only the hardware limit switch that lies in the direction in which the drive is being moved is
evaluated.
This enables you to move away from a hardware limit switch without additional error
acknowledgment by moving in the other direction if you reach or overrun a hardware limit
switch.
The current signal level of the digital inputs is displayed in the feedback interface, delayed by
the update rate.
You can see from the following table what effect the hardware limit switches have in the
individual MODEs:
MODE
Search for Reference
Inching
Absolute Positioning
Relative Positioning
326
Meaning
Type 0 means:
DO0 travel minus
•
DO1 travel plus
•
DO2 rapid/creep feed
•
Type 1 means:
DO0 rapid feed
•
DO1 creep feed (rapid feed is 0)
•
DO2 travel plus (1)/minus (0)
•
The digital outputs are switched off, and a
change of direction by T
min
delay.
T is effective at each change of direction
min
during a run.
T is not effective at startup after POS_DONE
min
= 1 or POS_ERR = 1.
Your input value is multiplied by 10. You thus
specify T in increments of 10 ms (for
min
example, 0 ms, 10 ms or 2550 ms)
Effect of the Hardware Limit Switches
The 1PosU executes an automatic reversal of direction on the hardware
limit switch.
The motion of the axis is halted on the hardware limit switch, all 3 digital
outputs are set to 0, and the POS_ERR feedback bit is reported.
Value range
•
•
0 - 255
is executed with a
Default setting
0
0
1
0
Operating Instructions, 05/2007, A5E00124871-04
ET 200S Positioning