The tensile testing machine is the main machine for tensile testing, and its tensile signal can be calibrated using two methods: standard dynamometer or electrical calibration, essentially adjusting and calibrating the measuring circuit. The measurement accuracy of a standard tensile testing machine can generally reach 0.15%, and it is connected in series to the force sensor of the testing machine. Adjust the "coarse balance" and "fine balance" of the phase balance and amplitude in the measurement circuit first, and then make the current output zero.
Slowly load again, when the tensile testing machine reaches the force value of the standard dynamometer, the value displayed by the force sensor and co amplifier circuit is the full load range. Adjust the amplification factor of the measurement amplifier to make the voltage value a standard value, such as 10v. Use this as the standard voltage. After unloading and performing several recalibrations, complete the full scale calibration, and then perform a linear check of a certain proportion of the range.
Due to the difference in gain of the same testing machine under different control states and specimens, and the need to adjust relevant parameters according to accuracy and width requirements, operators must continuously adjust relevant parameters according to test requirements to achieve excellent performance. The reasonable operation and adjustment of the electro-hydraulic control system of the testing machine are briefly introduced as follows.
When starting the machine, the control console should be powered on first, and then the hydraulic source should be activated. If the hydraulic source is activated first and the control console is not in a controlled state, on the one hand, the zero offset of the servo valve causes hydraulic oil to enter the hydraulic rainbow, causing the piston to move in one direction until it touches the cylinder cover, and sometimes even causing a cylinder collision accident; On the other hand, some electronic devices require top heating, especially circuits with strain gauges, which require preheating for more than half an hour to make the zero position more stable. Therefore, when starting up, the first step is to power on the console and check if all instruments are in normal condition. For testing machines with several control states such as position, force, and deformation control, the control state should be first placed at the position control position, and then switched to the corresponding control state as needed after all activation is completed.