應(yīng)遵守梯形圖語(yǔ)言中的語(yǔ)法規(guī)定設(shè)置中間單元在梯形圖中，若多個(gè)線圈都受某一觸點(diǎn)串并聯(lián)電路的控制，為簡(jiǎn)化電路，在梯形圖中可設(shè)置用該電路控制的輔助繼電器，類似于繼電器電路中的中間繼電器。分離交織在一起的電路 設(shè)計(jì)梯形圖時(shí)以線圈為單位，分別考慮繼電器電路圖中每個(gè)線圈受到那些觸點(diǎn)和電路的控制，然后畫(huà)出相應(yīng)的等效梯形圖電常閉觸點(diǎn)提供的輸入信號(hào)的處理設(shè)計(jì)輸入電路時(shí)，應(yīng)盡量采用常開(kāi)觸點(diǎn)，如果只能用常閉觸點(diǎn)，梯形圖中對(duì)應(yīng)觸點(diǎn)的常開(kāi)/常閉類型應(yīng)與繼電器電路相反。時(shí)間繼電器的瞬動(dòng)觸點(diǎn)的處理對(duì)于有瞬動(dòng)觸點(diǎn)的時(shí)間繼電器，可以在梯形圖中對(duì)應(yīng)的定時(shí)器的線圈兩端并聯(lián)輔助繼電器，后者的觸點(diǎn)相當(dāng)于時(shí)間繼電器的瞬動(dòng)觸點(diǎn)。斷電延時(shí)的時(shí)間繼電器的處理用通電后延時(shí)的定時(shí)器來(lái)實(shí)現(xiàn)斷電延時(shí)功能。外部聯(lián)鎖電路的設(shè)計(jì)在梯形圖中設(shè)置對(duì)應(yīng)的輸出繼電器的線圈串聯(lián)的常閉觸點(diǎn)組成的軟件互鎖外，還應(yīng)在PLC外部設(shè)置硬件互鎖電路。熱繼電器過(guò)載信號(hào)的處理

The intermediate unit shall be set according to the syntax provisions in the ladder diagram language. In the ladder diagram, if multiple coils are controlled by a series parallel circuit of a contact, in order to simplify the circuit, the auxiliary relay controlled by this circuit can be set in the ladder diagram, which is similar to the intermediate relay in the relay circuit. When designing the ladder diagram of separated and intertwined circuits, take the coil as the unit, respectively consider which contacts and circuits control each coil in the relay circuit diagram, and then draw the corresponding equivalent ladder diagram. When designing the input circuit, the normally open contact should be used as far as possible. If only the normally closed contact can be used, the normally open / normally closed type of the corresponding contact in the ladder diagram should be opposite to the relay circuit. Processing of instantaneous contact of time relay for time relay with instantaneous contact, the auxiliary relay can be paralleled at both ends of the coil of the corresponding timer in the ladder diagram, and the contact of the latter is equivalent to the instantaneous contact of time relay. The processing of the time relay of power-off delay uses the timer of power-on delay to realize the function of power-off delay. For the design of external interlocking circuit, in addition to the software interlocking composed of normally closed contacts connected in series with the coil of the corresponding output relay in the ladder diagram, the hardware interlocking circuit should also be set outside the PLC. Processing of overload signal of thermal relay