Temperature control system for reflux welder

Abstract

The invention discloses a temperature control system for a reflux welder, which comprises a programmable controller, a parameter setting unit, a plurality of temperature detection units and an upper monitoring machine connected with the programmable controller, wherein the plurality of temperature detection units are arranged in a plurality of temperature areas respectively; a plurality of electric heaters and a plurality of heating fans which are respectively arranged in the plurality of temperature areas are controlled by the programmable controller; a photoelectric probe is arranged on the reflux welder; a speed measuring probe is arranged on a traveling channel for work pieces inside the reflux welder; an electromagnetic switch for controlling and adjusting the heating power of the electric heaters is connected to a drive control circuit of the electric heaters in series, and the conduction angle of the electromagnetic switch can be controlled by the programmable controller. The temperature control system is reasonable in design, simple to operate and good in use effect, and solves the problem of large temperature fluctuation under large disturbance, and meanwhile, the problem of temperature control lag is solved, therefore, the temperature control system has the advantages that the heating speed is fast, no overshoot exists, the temperature fluctuation is small in the condition of inputting large work pieces, the cost is saved, and the like.

Description

technical field [0001] The invention belongs to the technical field of temperature control systems for reflow soldering machines, in particular to a temperature control system for reflow soldering machines. Background technique [0002] Most of the traditional temperature control methods use the electric signal that the thermocouple wire changes with the temperature change as the control signal to make fixed-point switch control on the electric heating element. During temperature control, when the temperature of the heated area rises to the set temperature, the temperature controller will send a signal to stop heating, but because the energy is transferred from the electric heating element to the heated area, it takes a process, and the time required for this process is the same as The heating element is related to the medium between the heated device, so when the heating signal stops, the internal temperature of the heating element will be higher than the set temperature, a...

AI Technical Summary

Problems solved by technology

However, in actual operation, the PID temperature control method will inevitably produce hysteresis, and it is difficult to meet the requirements of rapid response under large disturbances to form the minimum degree of overshoot and undershoot.

In summary, when the tunnel furnace and reflow machine input large workpieces, the above-mentioned PID temperature control method has defects such as temperature control lag, and it is difficult to meet the requirements of rapid response under large disturbances to form the minimum degree of overshoot and undershoot.

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