JPH05108167A - Controller - Google Patents

Abstract

PURPOSE:To detect the abnormality of a fluid control means and a controller itself by monitoring the fluctuation state of operation for a prescribed period of time from the start of the control of a mass flow controller with a sequence controller and detecting the abnormality of the mass flow controller. CONSTITUTION:A sequence controller 1, in which a set value for a flowrate and the allowable range and monitoring time of the flowrate are set, monitors the fluctuation of a gas flowrate within the monitoring time set immediately after starting gas supply and detects the abnormality of gas flowrate. When a mass flow controller 2 is abnormal, a set flowrate range (set value + or -2%) is not reached within 15 seconds and the abnormality is detected by the sequence controller 1. The fluctuation which occurs at the early stage of the supply of gas is not judged as abnormality because it remains within 15 seconds the same as that in a normal case. That is, the abnormal operation caused by the abnormality of the fluid control means 18 detected but the abnormal operation caused the other factor is not detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for controlling the flow rate of gas or the like.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional gas flow rate control device. 1a is a sequence controller, which is shown in FIG.
As shown in the graph, the set value and its allowable range (± 2
%) And a monitoring time for monitoring a state outside this allowable range are set, and if the gas flow rate is outside the allowable range of the set value and exceeds the monitoring time, it is detected as an abnormal gas flow rate. ..

Reference numeral 2 is a mass flow controller having an accuracy within ± 2% and a response time within 3 seconds, a maximum flow rate of 10 l / min and a working pressure range of 0.5 to 3.0 kgf /.
It has a specification of cm ² and controls the gas flow rate to a value set in the sequence controller 1. The sequence controller 1a sets the flow rate of the gas and the flowing time in the mass flow controller 2, and additionally detects an abnormality in the mass flow controller.

FIG. 6 is a piping diagram of a gas supply system of a semiconductor manufacturing apparatus using the conventional gas flow rate control device shown in FIG. The mass flow controllers 2a, 2b, 2c are the same as the mass flow controller 2 of FIG. 4 provided in the three gas lines, respectively, and the pressure of the gas supply source is 0.5 kg.
It is a pressure reducing valve that is adjusted to f / cm ² .

When a maximum flow rate of 10 l / min of the mass flow controller 2 is started in a state where no gas is flowing, the gas pressure applied to each mass flow controller 2a, 2b, 2c is 0.5 kgf / cm ² because the supply gas pressure is 0.5 kgf / cm ^2. Is 0.
It will be less than 5 kgf / cm ² .

This gas pressure deviates from the specification value that guarantees the performance of the mass flow controller 2, and as shown in FIG. 7, it takes a long time (10 seconds) until the gas flow rate stabilizes within the allowable range of the set value. It will cost you.

Here, when the content of the sequence controller 1a is set to a monitoring time of 3 seconds in accordance with the performance of the mass flow controller 2 as shown in FIG. 7, the gas pressure is the standard value (0. 5kgf / c
Since it has become less than m ² ), it will take 3 seconds or more (1
0 seconds), so the sequence controller 1a
Judges this state to be abnormal.

This state is an initial fluctuation of the supply gas pressure and is not an abnormality of the mass flow controller 2. Therefore, in order to avoid the above-mentioned inconvenience, the sequence controller 1a considers the performance of the normal mass flow controller 2 as shown in FIG. 5, and when the flow rate value outside the allowable range of the set value continues for 1 minute or more, Is considered abnormal.

[0009]

Since the conventional flow control device is constructed as described above, the mass flow controller 2 itself maintains the initial performance as shown in FIG. 8 instead of the fluctuation of the supply gas pressure. If the deterioration is such that it becomes longer than it was, the sequence controller 1a cannot detect this state as an abnormality of the mass flow controller.

On the other hand, if the monitoring time for setting the sequence controller 1a is shortened, other abnormalities such as fluctuations in the supply gas pressure that are not abnormal in the mass flow controller 2 will be detected.

The present invention has been made to solve the above problems, and an object thereof is to provide a control device having a setting monitoring means capable of detecting an abnormality in the fluid control means itself.

[0012]

The control device of the present invention comprises:
The operation is monitored for a certain period of time immediately after the start or change of the operation, and a setting monitoring unit is provided to make an abnormality when the state is different from the set value.

[0013]

The operation abnormality due to the abnormality of the fluid control means is detected, and the operation abnormality due to other factors is not detected.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a flow rate control device showing one embodiment of the present invention. Reference numeral 1 is a sequence controller in which a set value of flow rate as shown in the graph of FIG. 2, its allowable range (± 2%) and a monitoring time are set, and the gas flow rate within the set monitoring time immediately after starting the gas supply. The fluctuation is monitored to detect an abnormal gas flow rate.

Reference numeral 2 is the same mass flow controller as in FIG. When the mass flow controller 2 is abnormal, it differs from the normal case as shown in FIG.
Within a second, the set flow rate range (set value ± 2%) is not reached, and the sequence controller 1 determines that there is an abnormality.

On the other hand, the fluctuation that occurs at the initial stage of gas supply is within 15 seconds as in the normal case shown in FIG. 3, so it is not judged to be abnormal.

[0017]

As described above, according to the present invention, since the operation failure immediately after the start of control can be detected by the setting monitoring means, the abnormality of the fluid control means is not an abnormality such as the fluctuation of the operating environment of the apparatus. Can be detected.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a gas flow rate control device showing an embodiment of the present invention.

FIG. 2 is a correlation diagram of time and flow rate showing monitoring contents of the gas flow rate control device shown in FIG.

FIG. 3 is a time-flow correlation diagram showing normal operation and abnormal operation of the gas flow rate control device shown in FIG.

FIG. 4 is a configuration diagram showing a conventional gas flow rate control device.

5 is a correlation diagram of time and flow rate showing monitoring contents of the gas flow rate control device shown in FIG.

FIG. 6 is a piping diagram of a gas supply system of a semiconductor manufacturing apparatus using the conventional gas flow rate control device shown in FIG.

FIG. 7 is a correlation diagram of time and flow rate when gas is supplied using the gas supply system shown in FIG.

FIG. 8 is a correlation diagram of time and flow rate when there is an abnormality in the mass flow controller.

[Explanation of symbols]

 1 Sequence controller 2 Mass flow controller

Claims (1)

[Claims] 1. A flow rate control means for controlling a volumetric flow rate of a fluid, and an operating condition of the fluid control means is set to monitor the fluctuation of the operation immediately after the control operation of the fluid control means is started. A control device comprising a setting monitoring means for detecting an abnormality in the fluid control means.