Hi Aphie,
You can plot just the ASK price in eSignal. This can be done in both the Standard Charts and Advanced Charts.
For the Advanced Charts, with the AC chart as the active window, right click within the chart & select "Edit Studies". A Study properties dialog box will appear. At the top, you'll see a settings window titled, "Study:" Be sure the Tick study is selected, then just below you'll see another settings window titled, "Chart type:". Click on the down arrow to bring up the drop down menu & select, "Line/Tick". Remove check marks in all three categories for Trades & Bid. This will give you a tick chart for just the Ask.
In the standard charts, be sure you have it set to Tick Chart. Right click within the tick chart & select colors. Go to "Bid (Tick Charts Only)" highlight & click on Change Color button. Then change the color to be the same as the background color. Select OK & exit out. At top of the chart is a set of icons. Be sure the B/A icon is turned on (depressed) and the "TR" (Trade) icon is turned off. This will give you just the ask price.
Hope this helps.
Regards,
Andy S.
eSignal Support