Need help programming my bot to not re-enter trades where a trade already exists

Hi

I've done everything on my first bot, except it re-enters again for every candle that gets an entry signal, sometimes meaning I have 5/10/15 trades open at the same time. 

Please can you help? I've been at this specific problem for over 5 hours and I just can't wrap my head around it

Thanks 

Josh

*****Code is below:  ******

using System;
using System.Linq;
using cAlgo.API;
using cAlgo.API.Indicators;
using cAlgo.API.Internals;
using cAlgo.Indicators;

namespace cAlgo.Robots
{
    [Robot(TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
    public class HeavyweightBot : Robot
    {
        [Parameter("Instance Name", DefaultValue = "001")]
        public string InstanceName { get; set; }

        [Parameter(DefaultValue = 0.0)]
        public double Parameter { get; set; }

        //Selecting Indicator
        private ConvertedIndicator heavy;

        protected override void OnStart()
        {
            Print("Hello World!");
            //Load Indicators on startup
            heavy = Indicators.GetIndicator<ConvertedIndicator>(14, 3);


        }

        protected override void OnBar()
        {
            //Trade Amounts
            var TradeAmount = 1000;

            //Zero line cross example
            var HeavyUp = heavy.ExtMapBuffer2_AlgoOutputDataSeries.Last(1);
            var PrevHeavyUp = heavy.ExtMapBuffer2_AlgoOutputDataSeries.Last(2);
            var HeavyDown = heavy.ExtMapBuffer1_AlgoOutputDataSeries.Last(1);
            var PrevHeavyDown = heavy.ExtMapBuffer1_AlgoOutputDataSeries.Last(2);
            var Flat = heavy.ExtMapBuffer3_AlgoOutputDataSeries.Last(2);

            //Check for trade signal




            {


                if (HeavyUp > PrevHeavyDown)
                {

                    ExecuteMarketOrder(TradeType.Buy, SymbolName, TradeAmount, "Heavy", 20, 20);

                }




                else if (HeavyDown < PrevHeavyUp)
                {

                    ExecuteMarketOrder(TradeType.Sell, SymbolName, TradeAmount, "Heavy", 20, 20);
                }
            }
        }



        protected override void OnStop()
        {
            Print("Cya Later!");
        }

        #region Position Information

        /// <summary>
        /// 
        /// </summary>
        /// <param name="type"></param>
        /// <returns></returns>
        private bool IsPositionOpenByType(TradeType type)
        {
            var p = Positions.FindAll(InstanceName, SymbolName, type);

            if (p.Count() < 1)
            {
                return true;
            }

            return false;
        }

        #endregion
    }
}