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Start an EA from a script?

  • #1
  • First Post: Nov 5, 2010 5:11am Nov 5, 2010 5:11am
Hi,
do you have some example code at hand which I can add to my buy/sell script, which initiates an EA (which I have in the experts foldeR) on that chart where I run my script?

e.g., my buy script will not let me trail the trade, but my EA does. How do I combine that? Maybe also better suggestions from anyone?

Lowen
  • #2
  • Nov 5, 2010 12:49pm Nov 5, 2010 12:49pm
I have to assume that you have some programming skills and that for some reason you can't incorporate the script into the EA but you didn't provide very much explanation of your situation.

I would set the magic number in the OrderSend() function in the script that would indicate to the EA that is time to manage the trade. The EA would run continuously checking for a trade with the magic number.
  • #3
  • Nov 5, 2010 1:01pm Nov 5, 2010 1:01pm
We should see the script code or at least what does the script do.
Stop asking ChatGPT for broken MQL code. VisualMQL it instead.
  • #4
  • Nov 5, 2010 1:16pm Nov 5, 2010 1:16pm
thx CodeMeister,

well let me try to describe my situation:

I run my buy/sell script via hotkey to enter SL/TP & risk values and initiate a market or stop order therewith.

Now I have a seperate trailingStop-EA which I can drag to the chart window, where I again enter the SL value as a trailingStop base value.

But actually, I want to get rid of this inconvenient second step, I want to combine the 2 steps. But one is a script which I run per chart, and the 2nd is an EA I run in the same chart.

It would make life way easier If my buy order will automagically activate the EA and hand over some values (and at its best, also delete it from chart when the trade is over)
Maybe I can get around using a script, as the EA could also initiate the buy / sell?

So, yes CodeMeister your suggestion sounds good. Can I also hand over values from the script to the currently active EA?


Hmm I can give you more info but I guess u understand what I need..

EDIT: hi CodersGuru, I hope this explains it well enough?


Lowen
  • #5
  • Nov 5, 2010 1:31pm Nov 5, 2010 1:31pm
"Can I also hand over values from the script to the currently active EA?"
Yes, with GlobalVariableSet.
  • #6
  • Nov 5, 2010 1:39pm Nov 5, 2010 1:39pm
Quoting Kenz987
"Can I also hand over values from the script to the currently active EA?"
Yes, with GlobalVariableSet.
hi,
Never dealt with globalvariables..
and this globalVariable value, is it "global" per Magic Number, or could I only run one instance in MT4 at the same time, because the script would otherwise assign it to all running EAs (cause I have open more than one chart window, maybe running 2 or more trades)?
  • #7
  • Nov 5, 2010 1:43pm Nov 5, 2010 1:43pm
You can make Globals as unique as you need. You can use them to pass data among EA's and scripts on diff charts of the same MT4 terminal. They last for a month if not accessed and are basically a shortcut to reading/writing files. Very handy.
  • #8
  • Edited 2:05pm Nov 5, 2010 1:53pm | Edited 2:05pm
Ok, so would that be a wise way to go?

1) I have one buy/sell script which I will run everytime I wanna set a buy (stop-/limit- or market-) order.

2) The SL value which I entered in the script is a Global which can be assigned to the EA in the current chart (or, better, to the EA on the chart which corresponds to the pair I created the buy-order for)

3) The EA is already running in all charts, "waiting" for initialisation.
With my buy order getting active and the Global value, the chart-/pair-specific EA will have something to do.

So how can I tell the script to only give the Global to the EA in the current chart, or better, with the intended pair?
  • #9
  • Nov 5, 2010 2:05pm Nov 5, 2010 2:05pm
The idea in the second post is workable and doesnt use globals but is similar to the Global idea. Name the global something that identifies the currency pair/magic number and have the EA poll for it. When it finds it, extract the stoploss data stuffed in the Global. Go to town...
  • #10
  • Edited 2:22pm Nov 5, 2010 2:09pm | Edited 2:22pm
Quoting Aja
The idea in the second post is workable and doesnt use globals but is similar to the Global idea. Name the global something that identifies the currency pair/magic number and have the EA poll for it. When it finds it, extract the stoploss data stuffed in the Global. Go to town...
hmm I don't fully understand. Would that mean I have to create separate scripts/EAs for every pair?

Or, deciding for a way to go, would it be better to put everything in the EA. So I just run the EA by hotkey, enter the values, and then the buy order will be set and the EA knows about all the values it needs to trail the pair.. If so, I would just need a way to close the eA when the trade is over..
  • #11
  • Nov 7, 2010 9:51am Nov 7, 2010 9:51am
datetime GlobalVariableSet( string name, double value)
Sets a new value of the global variable. If it does not exist, the system creates a new gloabl variable. If the function succeeds, the returned value will be the last access time. Otherwise, the returned value will be 0. To get the detailed error information, one has to call the GetLastError() function.
Parameters:
name - Global variable name.
value - The new numeric value.
Sample:
//---- try to set new value
if(GlobalVariableSet("BarsTotal",Bars)==0)
return(false);
//---- continue processing
================
Think of them as in-core files, but they persist if there is a crash.
The "File Name" can contain the Symbol(), so it can be unique, and the value could be a 1 or 0 for yes/no, or could be a Magic Number for better control.
  • #12
  • Nov 7, 2010 12:00pm Nov 7, 2010 12:00pm
Quoting Lowen
hmm I don't fully understand. Would that mean I have to create separate scripts/EAs for every pair?

Or, deciding for a way to go, would it be better to put everything in the EA. So I just run the EA by hotkey, enter the values, and then the buy order will be set and the EA knows about all the values it needs to trail the pair.. If so, I would just need a way to close the eA when the trade is over..
Imo this is the best solution. To close EA, you can use this command:

PostMessageA(WindowHandle(Symbol(),Period()),WM_COMMAND,33050,0);

don't forget to import PostMessageA using:
#import "user32.dll"
int PostMessageA(int hWnd,int Msg,int wParam,int lParam);

hth,
sangmane
  • #13
  • Nov 7, 2010 5:11pm Nov 7, 2010 5:11pm
Hey guys,
thanks for your answers. I thought about this some more on the weekend, and think it might be a bit complicated to put everything in an EA, as I'd have to check for every tick if the buy or sell order has to be executed (normally it should only execute once). This is problematic in my eyes, especially when I switch timeframes and the like.

So I played around with your hints to use global variables.
I use my initial buy script, and set a global variable which has the name of the symbol(), and the value of the StopLoss which I set in that buy script..

script:
Inserted Code
extern double StopLoss = 200;

int start()
   { 
   GlobalVariableSet (Symbol(), StopLoss);


This global variable will be read by the EA and it currently looks this way (in the init()-section, not sure if that's correct).

EA:
Inserted Code
extern int TrailingStop = 100; 

int init()
  {
   if (GlobalVariableCheck(Symbol())==0)
      Print("Can not Get a Global Variable !"); 
   else TrailingStop = GlobalVariableGet(Symbol());   // <= will now be 200..
      Print("Successfully Got a Global Variable: " + TrailingStop);

My current problem now is the following:
I wish to have the chance to edit the TrailingStop-Value later on, using the EA property input window, which pops up if I press F7.

But if I create an extern in my EA for the Trailing, it will get overwritten by the GlobalVariable-assignment everytime I press F7..

What would be a good solution to get the initial trailing-value from the script like I do here, and then let me adjust that value later on in the EA-propertywindow?

Lowen
  • #14
  • Nov 7, 2010 6:46pm Nov 7, 2010 6:46pm
Quoting Lowen
Hey guys,
thanks for your answers. I thought about this some more on the weekend, and think it might be a bit complicated to put everything in an EA, as I'd have to check for every tick if the...
simply delete glb var after you got its value
int init()
{
if (GlobalVariableCheck(Symbol())==0)
Print("Can not Get a Global Variable !");
else {
TrailingStop = GlobalVariableGet(Symbol()); // <= will now be 200..
Print("Successfully Got a Global Variable: " + TrailingStop);
GlobalVariableDel(Symbol());
}
  • #15
  • Edited 4:25am Nov 8, 2010 4:08am | Edited 4:25am
Quoting sangmane
simply delete glb var after you got its value
int init()
{
if (GlobalVariableCheck(Symbol())==0)
Print("Can not Get a Global Variable !");
else {
TrailingStop = GlobalVariableGet(Symbol()); // <= will now be 200..
Print("Successfully Got a Global Variable: " + TrailingStop);
GlobalVariableDel(Symbol());
}
thanks a lot for that info. I will try this in the evening... sometimes it is easier as it seems
Hmm, thinking about this some more, wouldn't that mean that my Traillng stop value will be reset to default(100) if my EA initiates (with timeframe changing, rebooting and the like), as there is no Global Var anymore??

One more thing, and maybe a solution for this: How can I achieve, that the "TrailingStop" value (200, after getting value from Global) will be transfered to the UI (property window) of the EA. It always shows 100, as I declared it as default "extern int TrailingStop = 100; "


L
  • #16
  • Nov 8, 2010 5:48am Nov 8, 2010 5:48am
Quoting Lowen
thanks a lot for that info. I will try this in the evening... sometimes it is easier as it seems
Hmm, thinking about this some more, wouldn't that mean that my Traillng stop value will be reset to default(100) if my EA initiates (with timeframe changing, rebooting and the like), as there is no Global Var anymore??

One more thing, and maybe a solution for this: How can I achieve, that the "TrailingStop" value (200, after getting value from Global) will be transfered to the UI (property window) of the EA. It always shows 100, as I declared it...
i thought your problem was how to combine script and EA, ie how to retrieve script settings from EA (using glb var)?
  • #17
  • Nov 8, 2010 5:57am Nov 8, 2010 5:57am
Quoting Lowen
Maybe also better suggestions from anyone?
hey lowen..... quite possibly i'm missing something here but it sure seems to me it would be better to have a single trade management ea taking care of all pairs and trades..... this could be attached to any single chart, preferable an active one......

no matter what pair it was attached to it could make trades on any pair or trail trades on any pair if need be..... if there were no audjpy trades open, it would do nothing with respect to the audjpy..... once it saw an audjpy trade it would trail.....

the trailing stop amounts could be variable on a per pair basis on any metric..... such as if using the daily atr as the trailing stop amount, obviously it would be different for the gbpjpy than it would be for the eurusd..... or using the 20 ma...... or it could be a flat 100 across the board...... or adjustable depending on whether the trades were with or against the main trend.....

those type single ea setups can manage a couple hundred or a couple thousand orders on any amount of pairs with no trouble..... this i can verify, at least with ibfx......

set it and forget it.....

//-----

it might be better to continue making your initial trades in your normal manner, but the single ea could also make those trades on any pair.....

you should be able to find an example in my attachments folder........

//----

and as first mentioned, perhaps i'm missing something here...... h
to trade and code, keep both simple... no call to impress....h
  • #18
  • Edited 1:02pm Nov 8, 2010 12:30pm | Edited 1:02pm
Quoting sangmane
i thought your problem was how to combine script and EA, ie how to retrieve script settings from EA (using glb var)?
hi sangmane, thats correct. but, as I'm a bit picky °.O , I also need the possibility to switch timeframes etc, without the EA resetting it's current values..

It seems that's my only problem left (besides that I want the actual value in the property window, not sure how that's working)



Quoting hayseed
hey lowen..... quite possibly i'm missing something here...
hey,
hm I don't know. I want a trailing EA where I can easily press a button (i.e. F7) to adjust the Trailing Value of the current pair, not scroll down 50 extern variables.
I know some fancy trade management EAs, and they are not what I'm looking for. maybe later I will add sth. like ATR trailing, but atm it's more important for me, that I can, on the fly, access and change the few settings I currently need .
My trading is PA trading, not too much EA intervention neccessary, but trail.. and I will max trade 3 or 4 pairs at a time. But it's not intended as a "set and forget" ea..
Maybe, if I would use or create such EA, would it be possible that it only lets me buy/sell & adjust the pair for the active chart? that would perhaps do it.. but then, it needs to read and show the symbol(), and the currently used values I did set. And still, I'm confused how I would tell it if I just wanna adjust the trailing value, or if I want to buy/sell..

Definitely, it's important that I initiate the buy or sell manually. If the Ea can offer me that - fine, but I'm afraid that it's tedious to code the circumstances when it shouldn't reinitiate a new buy/sell order, but I bet u know better ...


Regards Lowen
  • #19
  • Nov 8, 2010 4:56pm Nov 8, 2010 4:56pm
Quoting sangmane
simply delete glb var after you got its value
int start()
{
if (GlobalVariableCheck(Symbol())==0)
Print("Can not Get a Global Variable !");
else {
TrailingStop = GlobalVariableGet(Symbol()); // <= will now be 200..
Print("Successfully Got a Global Variable: " + TrailingStop);
GlobalVariableDel(Symbol());
}
Hi sangmane,
deleting the global var seems to work. I have to put all the code in start(), not in init(), as otherwise the running EA would not recognize a new global variable from the buy script.
Is it ok to put that there like I do? It checks for the globalVariable every tick?


Strangely, by switching timeframes or even rebooting, the EA still keeps the last TrailingStop value stored - I thought extern variables get reset, but that isn't true.. I'm fine with that..



Now, my only problem is this: How do I get the Global Variable to show up in the extern variable "TrailingStop", when I open the EA property window??
Logically, it still shows the default value 100 there when I press F7, but the actual used value is that from the global Var..(as long as I do not manually adjust it)
Inserted Code
extern int TrailingStop = 100;
extern double StopTrailingAt = 10;
extern int    TrailingStep   = 1;

can't I write:
Inserted Code
extern int TrailingStop = GlobalVariableGet(Symbol());


I hope there's a neat solution so that the extern variable can be set to the global variable value, if it exists. But I'm almost afraid that's not possible, as outside of init() or start() the program is not run, so the property window cannot check if there's a global.. or..?

I'm really thankful for all your help,
Lowen
  • #20
  • Last Post: Nov 16, 2010 3:19pm Nov 16, 2010 3:19pm
ok now, there seems to be no way to put values the EA creates/gets in its process up there in the default input...

If anybody knows of anything that could help, please be so kind and write me a PM,

Lowen
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