Electronic sphygmomanometer measurement failure may have the following circumstances: First, when the screen appears E-1, may be the arm band is not tied to the measurement of no signal, or the pressure suddenly becomes large or small, at this time should be tied to the arm band, should not be too loose or too tight, the position should also be right; Second, when the screen appears E-2, there may be interference from other power devices around, such as cell phones, computers, etc., at this time away from the source of interference When the screen appears E-3, the air tube may be blocked, the air tube and air tube connector and blood pressure monitor body connection problems resulting in inflatable error, or the air tube and arm band rupture, then replace the new can; Fourth, when the screen appears E-5, indicating that the blood pressure is abnormal, can rest 30 minutes and then re-test, if three times in a row are appear abnormal blood pressure, it is recommended to go to the hospital to see if there are other reasons.