Get value from KNX and make script in LM

[Alexander]

I have tried this, but it doesn't work:

value = event.getvalue()

if value == 1 then
grp.checkwrite('29/0/6', 4)
end

if value == 0 then
grp.checkwrite('29/0/6', 3)
end

log(res, err)

The log is:
* arg: 1
* nil
* arg: 2
* nil