Inkjet printing system, fluid ejection system, and method thereof

A method of determining a supply condition of a fluid ejection system, the method comprising:

• establishing fluid communication between an ejection chamber having a nozzle corresponding thereto and a fluid supply chamber of a fluid ejection device by a channel;
• outputting voltage values by a micro-electro-mechanical system (MEMS) pressure sensor unit corresponding to a cross-sectional area of respective amounts of fluid in the ejection chamber;
• outputting count values by a converter module corresponding to the voltage values output by the pressure sensor unit, respectively;
• and
• determining the plurality of supply conditions by a determination module based on the count values output by the converter module, respectively;
• wherein the determining the supply condition by a determination module based on at least the count values output by the converter module, respectively, further comprises:
• determining an amount of time to refill the ejection chamber with the fluid from the fluid supply chamber by a refill determination module;
• and
• determining the supply condition by a count determination module based on the count values, respectively, output by the converter module and the amount of time to refill the ejection chamber determined by the refill determination module.