跑模拟账户，风险度控制不了。代码如下：

Params
   Numeric MaxRiskRatio(0.6); 
Vars
    Series<Numeric> LastEquity;                  // 最新权益
    Series<Numeric> FreeMargin;                  // 可用资金
    Series<Numeric> UsedMargin;
    Series<Numeric> CurrentRiskRatio;      
    Account acc;
Events
    OnReady()
    {
        Bool ret = A_GetAccount(acc, "66133512");
		CurrentRiskRatio = acc.available/acc.lastAmount;
    }
    OnBar(ArrayRef<Integer> indexs)
    {
        Commentary("CurrentRiskRatio:" + Text(CurrentRiskRatio));
        FreeMargin = Portfolio_CurrentCapital();
        UsedMargin = Portfolio_UsedMargin();
        LastEquity = FreeMargin + UsedMargin;
        If (LastEquity > 0)
        {
            CurrentRiskRatio = UsedMargin / LastEquity;
        }
        Else
        {
            CurrentRiskRatio = 1;
        }
        Commentary("LastEquity:" + Text(LastEquity));
        Commentary("CurrentRiskRatio:" + Text(CurrentRiskRatio));
        Commentary("acc.available:" + Text(acc.available));    
        //If(CurrentRiskRatio <= MaxRiskRatio) 开仓
    }

请问，哪里出了问题？谢谢！