Master-slave arrangement

HPLC systems operate on a master-slave arrangement in setting up for automation. One module sets the timing and initiates the process, and the remaining modules accept a signal and follow the leader. In a gradient HPLC system, the master module can be a microprocessor-based controller, a computer software-based controller, an autosampler, or an integrator. 

Medical Sources. All medical encapsulations are done in a facility which consists of a series of five interconnected stainless steel boxes which provide primary containment of process equipment and materials. Interconnections include transfer ports, drop-through tubes, and ventilation ducts. Each containment enclosure has a floor area of 1.52 m x 0.91 m the floor level is 0.76 m above the building floor. A pair of master-slave manipulators serve each containment box. A closed circuit television system and a telescope are provided for close-up viewing of incell operations and can be moved from cell to cell as needed. General arrangement of the facility is shown in Figures 13 and 14. 

With this arrangement, the output of one controller is used to adjust the set point of another. Cascade control can give smoother control in situations where direct control of the variable would lead to unstable operation. The slave controller can be used to compensate for any short-term variations in, say, a service stream flow, which would upset the controlled variable the primary (master) controller controlling long-term variations. Typical examples are shown in Figure 5.22c (see p. 235) and 5.23 (see p. 235). 

In order to achieve an accurate control of the internal reactor temperature, a cascade controller can be used. In this type of controller, temperature control is managed by two controllers arranged in cascade, that is, in two nested loops (Figure 9.14). The external loop, called the master, controls the temperature of the reaction mixture by delivering a set value to the slave, the inner loop, which controls the temperature of the heat carrier (Tc). 

The other type commonly in use has three sets of pins labeled 1 through 6. These six pins are arranged in three rows of two, with one set labeled master, another set labeled slave, and the third set with no label. With one drive installed, you leave all jumpers off. With two drives installed, you set the first drive (usually located at the end of the cable) tomaster by jumpering the two pins labeled master, then set the second drive to slave by jumpering the two pins labeled slave. ... 

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