Flowmeter, flow detecting switch, control method of flowmeter, control method of flow detecting switch, and recording medium having recorded a control program

A flowmeter comprising:

• a sensor portion to output a pulse signal having a frequency corresponding to a measured flow rate,
• a frequency measuring portion to measure the frequency of the pulse signal,
• an instantaneous flow rate calculating portion to calculate an instantaneous flow rate on a basis of the frequency of the pulse signal having been measured,
• an integrated flow rate calculating portion to calculate an integrated flow rate by integrating the instantaneous flow rate,
• and an indicating portion to indicate the instantaneous flow rate or the integrated flow rate,
• wherein the indicating portion is capable of indicating the integrated flow rate with an indication method of either a fixed-point system of a floating-point system selectively, and
• the indicating portion indicates the integrated flow rate, while switching indication of upper figures and lower figures of the integrated flow rate in turn.

A flow detecting switch, characterized by comprising:

• a sensor portion to output a signal corresponding to a measured flow rate,
• an instantaneous flow rate measuring portion to measure an instantaneous flow rate on a basis of the signal from the sensor portion,
• a comparing portion to compare the instantaneous flow rate value calculated by an arithmetic portion with a preset flow rate value having been preset, and
• a switch output portion to output either one of a high level signal and a low level signal, being a digital signal, on a basis of a comparison result of the comparing portion,
• wherein the comparing portion has two operation modes of a normal mode to compare the instantaneous flow rate value calculated by every first period with the preset flow rate value and a high-speed mode to compare the instantaneous flow rate value calculated every second period shorter that the first period with the preset flow rate value.

A flowmeter for carrying out flow measurement on a basis of a flow detection signal outputted from a flow sensor according to a flow rate of a measured fluid, characterized by comprising

• an instantaneous flow rate calculating means to calculate an instantaneous flow rate every fixed measuring period on a basis of the flow detection signal,
• an integrated flow rate calculating means to calculate an integrated flow rate by integrating the instantaneous flow rate,
• a judging means to judge whether or not the integrated flow rate has reached a preset integrated flow rate,
• an integration completion informing means to output an integration completion signal when the integrated flow rate has reached the preset integrated flow rate,
• an estimating operation means to calculate an estimated value of the integrated flow rate calculated by the integrated flow rate calculating means at a next measuring time-point and to judge whether or not the estimated value of the integrated flow rate reaches the preset integrated flow rate, and
• a measuring period controlling means to change the measuring period of the instantaneous flow rate calculating means to a shorter period when the estimating operation means has judged that the estimated value of the integrated flow rate at the next measuring time-point reaches the preset integrated flow rate.

A control method of a flowmeter for carrying out flow measurement on a basis of a flow detection signal outputted from a flow sensor according to a flow rate of a measured fluid, characterized by comprising the steps of:

• an instantaneous flow rate calculating step to calculate an instantaneous flow rate every fixed measuring period on a basis of the flow detection signal;
• an integrated flow rate calculating step to calculate an integrated flow rate by integrating the instantaneous flow rate;
• a judging step to judge whether or not the integrated flow rate has reached a preset integrated flow rate;
• an integration completion informing step to inform of an integration completion when the integrated flow rate has reached the preset integrated flow rate;
• an estimating operation step to calculate an estimated value of the integrated flow rate calculated by the integrated flow rate calculating step at a next measuring time-point and to judge whether or not the estimated value of the integrated flow rate reaches the preset integrated flow rate;
• and
• a measuring period controlling step to change the measuring period of the instantaneous flow rate calculating step to a shorter period when the estimating operation step has judged that the estimated value of the integrated flow rate at the next measuring time-point reaches the preset integrated flow rate.

A recording medium having recorded a control program for making a flowmeter carry out flow measurement on a basis of a flow detection signal outputted from a flow sensor according to a flow rate of a measured fluid, which recording medium having recorded a control program makes a flowmeter:

• calculate an instantaneous flow rate every fixed measuring period on a basis of the flow detection signal;
• calculate an integrated flow rate by integrating the instantaneous flow rate on a basis of an instruction from an outside;
• judge whether or not the integrated flow rate has reached a preset integrated flow rate;
• inform of an integration completion when the integrated flow rate has reached the preset integrated flow rate;
• calculate an estimated value of the integrated flow rate calculated at a next measuring time-point and judge whether or not the estimated value reaches the preset integrated flow rate;
• and
• change the measuring period for calculating the instantaneous flow rate to a shorter period when it has been judged that the estimated value of the integrated flow rate reaches the preset integrated flow rate.