I'm using VISSIM 11.00-13 and Matlab 2020a. I'm trying to control the signal heads of an intersection of 4 lanes from Matlab manually. I used for loop to run the green and yellow time respectively for each lane. At the end of the loop (period time 3600 seconds), it keeps giving me the following error: "Signal group 4: Attribute Signal state is no subject to changes". Any thoughts?