Question:
According to the software package positioner's default the limit switch signals are not connected to the digital inputs. Which modifications does the positioner template require in order to activate hardware limit switches to the digital inputs?
Answer:
The activation of the limit switches can be realized by an easy modification in the global variables (tab <Resources>, file Global Variables/TemplateInterface/VarHardwareSignals) in a way that the negative limit switch can be directly connected to terminal E1 and the positive one to E2:
1. Open the global user variables (file Global Variables/TemplateInterface/VarHardwareSignals).
2. Behind the variables
g_bLimitSwitchNeg and
g_bLimitSwitchPos delete the comment signs before and after the assignment to an absolute memory address ('AT %IX1.0.x'), so that the reference to the absolute address (= connection to the digital inputs E1 and E2) will become effective.
3. Delete the initialisation to the value TRUE or eliminate the corresponding part.
4. After successful modification in the global variables the declaration part of the user variable should be similar to the one shown below.
5. In the control configuration add the system block
DIGITAL_IO.
In contrast to the familiar 9300 EP positioning controller presentation style of
a TRUE signal when the limit switch is approached, as well as usage of the level inversion via codes C0114/00x (x = 1 ... 5) in the
positioner template the
limit switch signals are accepted
in the inactive status as TRUE (wire breakage protected). This is why these signals in case of operation without limit switch must be set to TRUE when the variables are initialised.
