This ProBuilder script is designed to manage a short trading position with dynamic exit strategies based on moving averages. It calculates position size based on risk management principles and adjusts orders based on real-time market data.

defparam preloadbars = 10000
defparam cumulateorders = false
// manually enter these variables
spread = 0.01
accountsize = 25000
entrylevel = 146.662
stoplosslevel = 146.937
eurusd = 1.0387
// calculate the desired loss and adjust the entry levels for spread
loss = 0.005*accountsize*eurusd
entrylevel = entrylevel -0.5*spread
stoplosslevel = stoplosslevel+0.5*spread
// calculate the desired position size
Positionsize = (loss / ((stoplosslevel-entrylevel) * (pipvalue/pipsize)/close))
// can only do 1 trade
c1 = TradeIndex(1) = 0
// Short entry order placement with stoploss
IF NOT ShortOnMarket and c1 THEN
    Sellshort Positionsize CONTRACTS AT entrylevel stop
    Exitshort at stoplosslevel STOP
ENDIF
// Initial stoploss placement
IF ShortOnMarket THEN
    Exitshort at stoplosslevel STOP
ENDIF
timeframe(1h, updateonclose)
// Trailingstop exits based on 1h MA10 and MA20 once in profit
once fullposition = 1
IF ShortOnMarket and trailingstop <= entrylevel THEN
    if close crosses over average[20] then
        Exitshort countofposition contracts at market
    else if close crosses over average[10] and fullposition = 1 then
        Exitshort (0.5*COUNTOFPOSITION) contracts at market
        fullposition = 0
        SET STOP $LOSS 0
    endif
endif
ENDIF

This script includes several key components:

• Parameter Initialization: Sets up necessary parameters like preload bars and order cumulation.
• Variable Setup: User-defined variables such as spread, account size, entry and stop loss levels, and currency conversion rates are initialized.
• Risk Calculation: The script calculates the monetary risk and adjusts the entry and stop loss levels based on the spread.
• Position Size Calculation: Determines how many contracts to trade based on the risk and the distance between the entry and stop loss levels.
• Order Placement: Conditional logic to place a short entry order if no short positions are currently held in the market.
• Stop Loss Management: A stop loss is set immediately after entering the market.
• Trailing Stop Logic: Utilizes a one-hour timeframe to manage the position with trailing stops based on moving averages (MA10 and MA20). The script exits half or the full position based on the crossover of these averages.

This example demonstrates how to integrate risk management and real-time trading adjustments using ProBuilder's programming capabilities.