Instructions On The Evaluation Of Input Signals - Siemens SINUMERIK 840Di sl Commissioning Manual

With active WCS, it is assumed implicitly In FC 26, that the first 3 axes in the machine axis
table are geometry axes. If this is not the case e.g. after the axis switchover, then the user
(machine manufacturer) must set the following output signal in the PLC user program:
● AB n + 2, Bit 6 (Axes 7 - n selected)
7.6.5.9

Instructions on the evaluation of input signals

Procedure for evaluating input signals
Press a softkey on HT 8 to set the associated signal in the input range to the value 1. A non-
defined number of PLC cycles correspond to the values in the input interface due to the non-
equidistant Ethernet communication. To avoid multiple initiation of functions, the evaluation
of the input signals in the PLC user program must be undertaken edge-triggered on the
positive edge of the signal.
Activating a function
An implementation option of activating a function with each positive edge of an input signal is
shown by the following listing:
OB 1 (excerpt)
CLR
U E
FBD G
= G
UN G
SPB M005
.....
M005: NOP 0
Manual
Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0
1.2 // If positive edge of user softkey U1?
101.1
101.3
101.3
// THEN
// Activating the function
// ENDIF
Ethernet communication
7.6 HT 8
219