Selections field relationship to Conditions

I have a trigger as follows: to Lay a horse with £2 stake

lay price lay_price Amount 2 Cancel
Selections = All Matching Selections
Markets = Win Markets
Execute = once per market
Market Status = In-Play

Then In my condition box I have:

Selections's LayPrice is less than 5
and Selections's triggerExpression winplace_back_matched is greater than 0

So I have backed a horse in place market via another trigger (this works fine)
Now in the win market I want to Lay this horse if it's odds are less than 5.
The problem is that I get an error in the log file as follows:

Error in the trigger expression of price or amount for selection "Afkar".


The log shows that the two conditions are true, so there is no error there.
But for some reason it doesn't like the price or the amount ??

Is it something to do with my Selections parameter being set to "All Matching Selections" ??

Thanks

In Settings, have you any limits on lay amounts that might be blocking the trigger execution?

Have checked the settings...don't have any limits on Lay_Amounts.

Hi
A couple of things you can check:

Your trigger operates inplay, fast moving prices. What is your setting for the frequency of updating the list of bets?

Was there a lay price?
selections lay price is between <your lowest acceptable lay price> and 5 will ensure there is a lay price available.

Hello.


Maybe it could also be the refresh rate ?: I have changed it to 0.5 for in-play.
When running again over the past few days...I still got the error...but sometimes it works.
So maybe a layprice was not available for the exact moment it went to Lay it ?


For in-play horse racing, would the following be ok ?
Update List of bets every 1sec
Refresh rate = 0.5 secs


Thanks

Hi
Just a few more thoughts:

The trigger logs will show if and why the error happens. Can you confirm your initial back bet in the Place market is always there? 

The trigger needs to look up a matched back bet in the opposite market, so effectively your lay trigger will be delayed by at least one refresh of the list of bets, by which time the price may be gone.

You refresh rates look ok, try updating the bets individually for each market to see if that is an improvement.

If any of your bets are below Betfair minimum, the time taken to submit the bet will be at least 3 times longer than a single bet.

Perhaps try to offer a lay price higher than the triggering price to increase the chance of getting matched:
in the price field use "best" according to the settings Betting Options > When laying at best price...
or in the price field use r_ticks(lay_price,x) where x is number of ticks higher than lay_price
Betfair will always match the bets at the best available price.