I am working with Chaotic System's circuit and i have built the circuit of Lorenz attractor using OPAMPs in MULTISIM. Whenever i use initial conditions as user defined(under interactive tab) as 28, 12 and 10, convergence error occurs but when i reduce the conditions to 0.28, 0.12, and 0.10, the circuit works. For other circuits also, the circuit works for small Initial conditions only. Somebody help me and give me a concrete solution to deal with this situation. I want the circuit to work at 28, 12 and 10.