US 4,063,077 A · Solvent programmer controller

Abstract

A controller for solvent programmer apparatus that produces programmed solvent mixtures for introduction to a liquid chromatographic analyzer. Under the direction of the controller, the solvent programmer accesses first and second solvents during a defined cycle of operation and proportions the solvents on the basis of the time within the cycle of operation that each solvent is accessed. The controller has a first counter that defines the cycle of operation and a second counter that is preset at the beginning of a cycle to a value representative of the percentage of the first solvent that is to be in a solvent mixture produced during the cycle. The second counter is then counted down. Output control logic responsive to the count states of the counters sends a command for the first solvent to be accessed upon the first counter reaching its maximum count, occurring at the beginning of a cycle, and sends a command for the second solvent to be accessed upon the second counter reaching its minimum count, with accessing of the first solvent being discontinued contemporaneously. The value of the percentage of the first solvent is held in data storage means. In isochratic operation of the solvent programmer, the value stored remains fixed and is repeatedly loaded into the second counter. In gradient operation of the solvent programmer, a counter in the data storage means, after being preset to an initial percentage value, is counted up at some predetermined rate, with the new value stored being loaded into the second counter. The rate of change with time of the contents of the data storage means can be either linear or non-linear.

Claims11

Dependent claims

In a solvent programmer apparatus that provides programmed solvent mixtures for introduction to a liquid chromatographic analyzer by accessing first and second solvents during a defined cycle of operation and proportioning the same on the basis of the time within the cycle that each solvent is accessed, a controller comprising:

a time base generator for generating a timing clock signal of a prescribed frequency;
first and second counters receiving the timing signal from said time base generator;
said first counter defining a cycle of operation within which the solvents are proportioned;
data storage means for holding a representation of the percentage value of the first solvent that is to be in a mixture produced by the solvent programmer;
and
output control logic responsive to the count value in said first and second counters for causing
the first solvent to be accessed upon said first counter reaching a prescribed count that indicates the beginning of a cycle of operation and
the second solvent to be accessed for the remainder of the cycle of operation, upon said second counter reaching a prescribed count which is dependent upon the percentage value stored in said data storage means, with access of the first solvent being discontinued.

5 more elements

a time base generator for generating a timing clock signal of a prescribed frequency;
an up counter receiving the timing clock signal, said up counter defining each of a series of cycles of operation within which the solvents are proportioned;
a down counter receiving the timing clock signal, said down counter defining the portion of each cycle of operation that the first solvent is accessed;
data storage means for storing a digital representation of the percentage value of the first solvent that is to be in a mixture of the solvents produced by the solvent programmer during a cycle of operation;
and
output control logic responsive to the count value in said up counter and in said down counter,
said control logic causing the first solvent to be accessed upon said up counter reaching the maximum count and the digital representation stored in said data storage means to be loaded into said down counter during each cycle, and
said control logic causing the second solvent to be accessed during the remainder of each cycle and access of the first solvent to be discontinued upon said down counter reaching the minimum count.

5 more elements

Dependencies are inferred from the claim text.

Solvent programmer controller

Life of this patent

Solvent programmer controller

Life of this patent

Abstract

Claims11