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SEMI F53-0600 © SEMI 2000 2 5.1.18 V — v o lt 5.1.19 V/m — volts/meter 5.2 Definitions 5.2.1 condu cted susceptibility — eq u i p ment vulnera- bility to conducted e missions. 5.2.2 el ectromagnetic — all en ergy o f e l…

SEMI F53-0600 © SEMI 20001

SEMI F53-0600

TEST METHOD FOR EVALUATING THE ELECTROMAGNETIC

SUSCEPTIBILITY OF THERMAL MASS FLOW CONTROLLERS

This test method was technically approved by the Global Facilities Committee and is the direct responsibility

of the North American Facilities Committee. Current edition approved by the North American Regional

Standards Committee on March 2, 2000. Initially available on www.semi.org April 2000; to be published

June 2000.

1 Purpose

1.1 The purpose of this document is to define a

structured method for testing and evaluating the

electromagnetic susceptibility of thermal mass flow

controllers.

2 Scope

2.1 This document contains the requirements and test

method that can be used to evaluate whether a thermal

mass flow controller will maintain its functional

characteristics when subjected to EMI levels typical of

the industry. The test method covers both the radiated

susceptibility (RS) and conducted susceptibility (CS) of

the controller when exposed to EMI. The

electromagnetic susceptibility requirements are

extracted from MIL-STD-461C and SAMA PMC-33.1,

and the test method is a composite of the RS03, CS01,

CS02, and CS06 test methods defined in MIL-STD 462.

2.2 This test method does not purport to address safety

issues, if any, associated with its use. It is the responsi-

bility of the users of this test method to establish

appropriate safety and health practices and determine

the applicability of regulatory limitations prior to use.

3 Limitations

3.1 This test method is not designed for AC-powered

MFCs. The test method addresses electromagnetic

susceptibility of MFCs through DC power leads and

control signals.

4 Referenced Standards

4.1 Military Standards

MIL-STD-461C  Electromagnetic Emission and

Susceptibility Requirements for the Control of

Electromagnetic Interference

MIL-STD-462  Measurement of Electromagnetic

Interference Characteristics

1 Available from Naval Publications and Forms Center, 5801 Tabor

Ave., Philadelphia, PA 19120

MIL-STD-463A  Electromagnetic Interference and

Electromagnetic Compatibility Technology Definitions

and Systems of Units

4.2 Scientific Apparatus Makers Associations

SAMA PMC  33.1 Electromagnetic Susceptibility of

Process Control Instrumentation, Scientific Apparatus

Makers Associations

NOTE 1: As listed or revised, all documents cited shall be the

latest publications of adopted standards.

5 Terminology

5.1 Abbreviations and Acronyms

5.1.1 CS — conducted susceptibility

5.1.2 dB — decibels

5.1.3 DC — direct current

5.1.4 EMC — electromagnetic compatibility

5.1.5 EMI — electromagnetic interference

5.1.6 GHz — gigahertz

5.1.7 kHz — kilohertz

5.1.8 MFC — mass flow controller

5.1.9 MHz — megahertz

5.1.10 MIL-STD — Military Standard

5.1.11 psia — pounds per square inch absolute

5.1.12 psig — pounds per square inch gauge

5.1.13 RF — radio frequency

5.1.14 RG-58 — a specification for a particular type of

coaxial cable

5.1.15 rms — root mean square

5.1.16 RS — radiated susceptibility

5.1.17 T — teslas

2 Portions of this method are excerpted from SAMA Standard PMC

31.1-1980 with permission of the publisher, Process Measurements &

Control Section, SAMA, 1101 16th St., N. W. Washington, DC

20036

SEMI F53-0600 © SEMI 2000 2

5.1.18 V — volt

5.1.19 V/m — volts/meter

5.2 Definitions

5.2.1 conducted susceptibility — equipment vulnera-

bility to conducted emissions.

5.2.2 electromagnetic — all energy of electrical or

magnetic nature; i.e., electric current flow or magnetic

field.

5.2.3 electromagnetic compatibility — the capability

of electronic equipment or systems to be operated in the

intended operational electromagnetic environment at

designed levels of efficiency.

5.2.4 electromagnetic interference — impairment of a

wanted electromagnetic signal by an electromagnetic

disturbance.

5.2.5 ground — a conducting conne ction, whether

intentional or accidental, by which an electric circuit or

piece of equipment is connected to the earth, or to some

conducting body of relatively large extent.

5.2.6 limit — the level of susceptibility that a stated

standard allows.

5.2.7 noise (electrical) — unwanted electrical signals

that produce undesirable effects in the circuits of

control systems in which they occur.

5.2.8 radiated susceptibility — equipment vulnerable

to radiated emissions.

5.2.9 stable — the state a signal level obtains when its

magnitude varies by less than or equal to ± 2.0% of full

scale over a one minute period.

6 Summary of Method

6.1 This test method describes the test equipment and

procedures for determining if the thermal mass flow

controller is susceptible to both radiated and conducted

interference. Initially, the controller is exposed to

radiated electric fields over a frequency range from 14

kHz to 1 GHz at field strength levels less than 10

volts/meter (V/m). Furthermore, the controller’s power

leads will be tested for susceptibility to voltage

transients with 10 µs rise times. See flow chart of the

test method, Figure 1.

7 Interferences

7.1 MFCs are located in areas where electromagnetic

(EM) fields are present. If an MFC is susceptible to the

fields, then the delivered flow by the MFC could be

adversely effected. The magnitude of the EM field’s

effect on the MFC performance shall be quantified by

this test method.

8 Apparatus

8.1 Radiated Electric Field Susceptibility (RS-03)

8.2 Signal Generator, 14 kHz to 1 GHz

8.3 Audio Power Amplifier, 14 kHz to 1 MHz

8.4 RF Power Amplifier #1, 1 MHz to 400 MHz

8.5 RF Power Amplifier #2, 500 MHz to 1 GHz

8.6 Field Strength Meter

8.7 Oscilloscope

8.8 Parallel Element Antenna, 14 kHz to 20 MHz

8.9 Biconical Antenna, 30 MHz to 200 MHz

8.10 Conical Log Spiral Antenna, 300 MHz to one

GHz

8.11 Tripod

8.12 Coaxial Cable, 50-ft, RG-58, with BNC male

plugs at each end.

8.13 X10 Attenuator Scope Probe

8.14 Assorted Coax Cables for Interconnects

8.15 Flow Standard — Installed downstream and in

series with the flow through the MFC. The flow

standard shall be capable of measuring flow to within ±

0.3% of full scale.

8.16 Flow Output Monitor — Connected to the MFC

output and signal common/ground points. The

monitor/recorder shall be capable of measuring over a

range of 0–10 VDC to within ± 5 mV.

8.17 Transient Susceptibility of Power and Control

Leads (CS-06) (Conducted Susceptibility)

8.18 Spike Generator, with series and parallel outputs

8.19 Oscilloscope, dual channel

8.20 X10 Attenuator Probe

8.21 X100 Scope Attenuator Probe, two each

8.22 Test Leads, 12-in long with banana plugs at each

end, four each

9 Reagents and Materials

9.1 Test Gas — Nitrogen with a dew point of less than

or equal to -40°C and at a source delivery pressure of

35 psig.

10 Safety Precautions

10.1 Safety Precautions — This test method may

involve hazardous materials, operations, and equip-

ment.

SEMI F53-0600 © SEMI 20003

10.2 The user must have a working knowledge of the

respective instrumentation, must practice proper

handling of test components, and must understand good

laboratory practices. The user should not operate the

components in such a manner as to exceed the ratings

(i.e., pressure, temperature, flow, and voltage).

10.3 Technical Precautions — These tests are to be

performed in a shielded or screened room to prevent

possible problems with nearby instrumentation or

electrical systems caused by the EM fields. At a

minimum, the instrumentation associated with this test

series (see Figure 2) must be shielded from the EM

fields to ensure their proper operation.

11 Preparation of Apparatus

11.1 The test gas source and delivery system must be

capable of satisfying the test volume flow rate at a

constant pressure, ± 0.1 psia.

11.2 The test gas source and delivery system must be

capable of delivering a gas at ambient temperature ±

1°C for the duration of each analysis. The ambient

temperature shall be held to 22°C ± 1°C.

12 Calibration and Standardization

12.1 For each test, verify that calibration of test

equipment is up-to-date.

13 Procedure

13.1 Install the MFC into the test setup per

manufacturer’s recommendations.

13.2 Apply power to all devices sho wn in Figure 3 per

manufacturer’s specifications. Allow the devices to

warm up for the duration specified by the equipment

manufacturer.

13.3 Purge the system with nitrogen for a length of

time equal to ten times the amount of time it takes to

replace the system volume once, when the test MFC is

at its full-scale rated flow rate.

13.4 Close inlet shut-off valve. Then close the outlet

shut-off valve located adjacent to the MFC (see Figure

2). Adjust the MFC setpoint to zero flow. Wait for the

signals to become stable. Record the following on the

data sheet:

• MFC indicated flow,

• Flow standard flow,

• Ambient temperature,

• Gas temperature, and

• Gas pressure.

13.5 Ensure that the inlet and outlet shut-off valves

adjacent to the MFC (see Figure 2) are open. Adjust

the MFC setpoint to 50%. Ensure that all

manufacturer’s recommended conditions are met for the

MFC. Once the output signals become stable, record

the MFC output signal, the flow standard output signal,

the ambient and gas temperature, and the gas pressure

on the data sheet in Table 1.

13.6 Ensure that the MFC power leads and control sig-

nal cables are shielded in the area that will be irradiated

by the EM fields. The cable shielding shall be intact up

to the connector. The type of shielding and connector

shall be recorded on the data sheet in Table 1.

13.7 Radiated Electric Field Susceptibility (RS-03)

13.7.1 Testing from 14 kHz to 20 MHz:

13.7.1.1 Mount the parallel element antenna on a

tripod at a distance of one meter from the controller and

connect the antenna to the audio power amplifier using

the 50-ft length of RG-58 coaxial cable (see Figure 3).

Set the switch to low frequency range.

13.7.1.2 Connect the amplifier input to the signal

generator output.

13.7.1.3 Turn on amplifier and signal generator.

13.7.1.4 Using the X10 probe, connect the scope

across the antenna terminals.

NOTE 2: It is important to use the X10 probe rather than a

coax that terminates in 50 ohms. The audio amplifier will not

drive the required voltage into 50 ohms.

13.7.1.5 Set frequency output of the signal generator

to 14 kHz.

13.7.1.6 Turn off signal generator modulation and set

voltage across the antenna input connector at 35-V rms.

NOTE 3: With this voltage applied to the antenna at

frequencies below one MHz, the required field strength of 10

V/m at a distance of one meter from the antenna should be

established.

13.7.1.7 If, at any frequency, the required voltage

cannot be developed across the antenna terminals, set to

the maximum possible without exceeding equipment

ratings.

13.7.1.8 When voltage is set, turn on modulation and

adjust for 50% amplitude modulation with the internal

one kHz source.

13.7.1.9 Check operation of the controller in the

presence of this radiated field. Record the MFC

indicated flow, flow standard output, and the frequency

on the data sheet in Table 1.