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Updating Markets - Guardian Market Cycling

Refresh Interval
Bet Angel Guardian cycles through all markets loaded in Guardian using the 'Refresh interval' defined by the user on the main ribbon. 
Each time a market is refreshed it's price & bet information is updated, you can see the time a market was last updated by looking at its 'Last update' cell in the market list window.
When a market is updated, Guardian executes any management tasks it has for that market (knowing that it now has the most up to date price and bet information available). These management tasks may include: binding the market with Excel, executing Advanced Automation rules, acting upon global settings such as stop losses, and capturing new chart data points.
Market Cycling
To explain market cycling in more detail: If, for example, your Guardian refresh interval is set to the default 1 second, then Guardian will update each market in turn once per second. 
If you have 20 markets loaded in to Guardian it will then take 20 seconds to cycle through all of the markets. So you'll only be refreshing prices (triggering automation rules, creating a chart data point etc) for each market once every 20 seconds.
If you were to increase the refresh rate to 200 milliseconds then each of those 20 markets would now be updated every 4 seconds.
At full speed refreshing at 20 milliseconds each market would be updated at least twice EVERY second!
Care should still be taken not to add an unnecessarily large quantity of markets to the market list. Even with streaming the time taken to cycle from one end of the list to the other may mean you miss market suspensions, automation trigger opportunities etc.
Unless a market is updated, Guardian cannot perform its management tasks, so it is vital that you configure Guardian refresh settings appropriately for the task you have given it.
Since Betfair introduced the option of 'Streaming' market data in 2016 we would recommend using this where possible.
With streaming enabled you can now get market updates as fast as every 20ms meaning any automation rules can be run against 50 markets every second.
Tip: In the case of soccer matches, rather than keep every one of today's matches in the list, why not click the 'Traded Volume) column header to sort markets by their traded volume and discard the ones with little or no volume.  They will be so illiquid that they will be untradable and their presence in Guardian market list makes the refresh of other markets less effective.
Note: If the market is opened on the main Bet Angel trading screen, then the market data will be updated at that screen's refresh rate. This is a great way to give a single market a high refresh rate (see Auto-Switch Market below for further details).
Advanced Settings - Restricted Refresh
This is a handy option if you wish to only monitor markets that are close to the event's start time. Ticking ‘Restrict refresh’ means Guardian will only monitor the markets whose start times are within the time window specified. The default setting is for Guardian to only refresh the markets that are within 20 minutes of starting until 15 minutes after. These times are taken from the advertised start time on Betfair. If a meeting is delayed then you will need to adjust the start times accordingly within Guardian.  You should also ensure your PC's local time is set accurately as this is used when comparing against the event's start time.
In the case of horse or greyhound racing automation, where each race is one after another, using restricted refresh is a great way to speed up the frequency of updates for the races about to start whilst ignoring those which are not yet of any interest.
Excel Tip: When used in conjunction with the ‘Auto-bind’ facility mentioned here, Guardian will only bind a market to your Excel spreadsheet when it has a start time within ‘Restricted refresh’ time window.
Auto-switch market
If Guardian is set to 'Automatically switch Bet Angel market' then the current market is automatically loaded into the main Bet Angel trading screen and is available for use by the features linked to that (one-click, ladder, in-play trader, Tennis Trader, Market Overview etc).  The market on the Bet Angel trading screen is updated based on its own refresh rate and is independent of the Guardian refresh cycle. 
When automating in-play horse races, where time is of the essence, it is recommended that you use this feature to ensure a rapid refresh of market data.