一种用于样品前处理的加液仪控制系统设计

Design of a adding liquid instrument control system for sample pretreatment

针对人工检测食品或者化学样本时,前处理误差大、效率低等问题,设计了一套用于样品前处理的加液仪控制系统。该系统采用PLC作为主控制器,根据前处理仪的控制需求,对系统的软硬件进行设计。结合S型加减速算法的特性和非接触式加液的特点,通过控制加液过程中减速阶段的加速度,让针尖悬挂液滴更好地脱落,提出了一种适合加液的分段式电机控制模型,并对加液体积进行了拟合分析和误差补偿。试验结果表明,其加液误差在±0.5%以内,满足了前处理仪设计的加液精度要求(±1%),且具有96个样品位,适合大批量的样品进行前处理。

When manual testing food and chemical samples,there are problems such as large pretreatment errors and low efficiency.In order to solve those problems,a adding liquid instrument control system for sample pretreatment was designed.The system adopts PLC as the main controller,and the software and hardware of the system were designed according to the control demand analysis of the pretreatment instruments.Combined the characteristics of the S-type acceleration and deceleration algorithm and non-contact liquid addition method.By controlling the acceleration of the deceleration phase during the liquid addition process for the droplet hanging on the tip falling off better,a segmented motor control model suitable for adding liquid was proposed.Finally,the fitting analysis and error compensation were performed on the dosing volume.The experimental results showed that the adding liquid error is within±0.5%.less than the specified±1%,whitch satisfies the adding liquid precision requirements of the pretreatment instrument,and has 96 sample positions,which is suitable for pretreatment of large batches of samples.