Electronically Controlled Needle Valve Features Comparison

1. Upstream flow control MKS valve
Abstract: Based on 148J, 248A and 154A series upstream flow control valves and 244, 250, 946 and 651 series controllers of MKS Corporation in the US. This article will introduce corresponding localized alternative products electronically controlled needle valve and multi-functional high-precision controllers. Also, the corresponding characteristics and technical indicators of the localized substitute products are introduced.
MKS upstream flow control valve is a type of vacuum electromagnetic proportional valve, as shown in Figure 1, there are three series of products: (1) 148J all-metal flow control valve: metal seal, flow range 0.01~20L/min. (2) 154B large flow control valve: rubber seal, flow range 20~200L/min. (3) 248D universal flow control valve: rubber seal, flow range 0.01~50L/min.



2. MKS flow/pressure controller The flow/pressure controller of MKS is a type of PID controller, as shown in Figure 2, mainly has the following 4 series of products:
(1) 244 series: manual PID control, single-channel control, suitable for various sensors, 0~10VDC input signal, manual/automatic/external control mode, accuracy is 0.25% of full scale, multiple set points (3 or 4), control deviation indicator. This model series of controller is discontinued now.
(2) 250 series: manual PID control, single-channel control, suitable for a variety of vacuum sensors, 0~10VDC input signal, manual/automatic/external control mode, accuracy is 0.25% of full scale, up to 4 set points, external programming setting, digital display of measured value and control deviation value. This model series of controller is discontinued now.
(3) 946 series: automatic PID control, 16-bit A/D acquisition, 6-channel control, suitable for a variety of vacuum sensors. It can monitor up to 6 sensor signals at the same time, 0~10VDC input/output signal, manual/automatic/external control Mode, internal programming, digital display of measured value and control deviation value, 12-way relay output, RS232/485 communication.
(4) 651 series: self-regulating fast PID control, 16-bit A/D acquisition, single-channel control, suitable for a variety of vacuum sensors, 0~10VDC input/output signal, manual/automatic/external control mode, repeatability is full scale of ±0.1%, external programming, digital display of measured values, multi-channel I/O interface, RS232/485 communication.




3. Localized electronically controlled needle valve directly replaces MKS solenoid control valve
The upstream flow control valve of MKS is a traditional solenoid valve. The biggest problem of solenoid valve is that hysteresis is relatively large, which will obviously affect linearity and control accuracy. The overall price of these control valves is relatively high, and there is no corresponding local brand. In order to reach the localized replacement of upstream flow control valves and improve cost efficiency, we use stepper motors to replace solenoid valves in needle valve technology, and develop a series of electronically controlled needle valve with different flow rates. As shown in Figure 3 and Figure 4, the replacement of localization has been fully achieved.
Please visit https://www.genndih.com/proportional-flow-control-valve.htm

Model	FC-20	FC-120	FC-300	FC-1000
Valve Type	Needle valve
Driver	Bipolar stepper motor control
Response Time	0.8sec (Open to close)
Standard Size	G 1/8”	G 3/8”
Fluid	Inert gas and liquid Pressure
Range	-1 ~ 7 bar	-1 ~ 5 bar
Flow Range	3× ~75L/min	0.01 ~ 30L/min	0.2 ~ 200L/min	0.1 ~ 50L/min
Maximum Flow	50L/min @7bar	240L/min @7bar	290L/min @7bar	600L/min @7bar
Linearity	2%	0.1 ~ 1%	0.2 ~ 5%	11%

 

Repeatability (Full scale)	1%
Flow Resolution (Step length)	0.1L	0.1 ~ 0.2L	0.2 ~ 0.75L	1L
Shift Resolution	12.7 um	25.4 um
Operating Temperature Range	0 ~ 84ºc
Seal	Standard FKM or other choices of seals
Control Signal	DC: 0 ~ 10V (or 4 ~ 20mA)
Power Supply	DC: 24V (12W)

4. Localized high-precision PID controller replaces MKS controller
The gas flow/pressure control of MKS is a dedicated controller, which can only meet gas flow and pressure control in vacuum field. Although it is very powerful, it is more expensive. The PID controller replaced by localization adopts a 24-bit A/D collector with higher precision. The controller is more versatile and can reach the simultaneous control of temperature and vacuum pressure, as shown in Figure 5. The main features are as follows:
(1) High precision: 24-bit A/D acquisition, 16-bit D/A output.
(2) Multi-channel: independent 1-channel and 2-channel.
(3) Multi-function: 47 kinds of input signals (thermocouple, thermal resistance, DC voltage) can reach simultaneous testing, display and control of different parameters, and can perform forward and reverse control (two-way control mode).
(4) PID control: The improved PID algorithm supports PV differential and differential advance control. 20 groups of group PID, group output limiter function.
(5) Dual sensor switching: Each channel can support dual sensor switching of high and low temperature and high and low vacuum. Two channels can form a control combination with a total of four sensors connected.
(6) Program control: support 20 process curves, each with 50 segments, support internal cycle and curve cycle.