Fluid valve control system for controlling fluid pressure or flow

Claim 1

In a fluid valve control system comprising a setting means for setting a desired flow rate or pressure of fluid and a desired control pattern, a pulse generating means for generating pulse signals corresponding to a controlled variable and a control pattern set by said setting means, and an actuating means for actuating said fluid valve in accordance with the pulse signals generated by said pulse generating means, the improvement comprising: a first memory means for storing a plurality of different pulse number data blocks corresponding in number to a number of control pulses required for a maximum controlled variable of said fluid valve, each of said pulse number data blocks consisting of pulse number data obtained by dividing a given number of control pulses corresponding to the controlled variable of said fluid valve by a number N, said pulse number data being stored in N divisions such that a sum of pulse numbers stored in the respective divisions is equal to said given number of control pulses; and a second memory means for storing control pattern data consisting of a plurality of different pulse period data blocks, each of said pulse period data blocks consisting of pulse period data stored in N pulse period divisions corresponding to said N divisions: wherein said pulse generating means includes: a timer means in which pulse period data T 0 to T N-1 of the respective pulse period divisions A 0 to A N-1 in a specified pulse period data block stored in said second memory means are preset one after another, wherein said timer means issues pulses of preset pulse periods; a first counter in which pulse number data n 0 to n N-1 of the respective divisions A 0 to A N-1 in a specified pulse number data block stored in said first memory means are preset one after another, wherein said first counter counts said pulses issued from said timer means and produces an output whenever the counter coincides with a preset pulse number; and a second counter for presetting, in response to a count output of said first counter, the pulse number data and pulse period data of the next divisions in said first counter and said timer means, respectively, wherein said second counter inhibits the issuance of pulses when its count coincides with the number N of divisions.