CS114 is a conducted susceptibility test method imposed on nearly all military and space electronics. EMI Analyst manages its conditional injection levels effortlessly.

1. EMI Analyst™
EMI ANALYST™ Software Suite
I n t u i t i v e  A c c u r a t e  E f f e c t i v e
CS114 Analysis Settings
Using EMI Analyst to perform method CS114
Analyses for MIL-STD-461

2. EMI Analyst™
Use EMI Analyst to Perform CS114 Analyses
CS114 has conditional injection levels
1. Inject the power drive level recorded during pre-test calibration
or…
2. Inject twice the specified current limit,
…whichever is reached first
Settings for EMI Analyst are shown on the following page.
For more details, read on…

3. EMI Analyst™
EMI Analyst Settings for CS114 Dual Limit
The CS114 current limit is entered using
the Limit property form
Injected power level is defined using the
Threshold property form

4. EMI Analyst™
CS114 Limit Curves Map Directly to EMI
Analyst Limit Form
Limit Form Settings MIL-STD-461 CS114 Limit Curves

5. EMI Analyst™
Threshold Form Settings Capture CS114
Properties
Settings
• Option
• Pretest Calibration – Closed Loop Method
• Calibration Fixture Impedance
• 100 ohms
• Pretest Units
• Watts or dBm
• Margin Units
• Same units as Limit form (dBA)
• Margin
• 6 (dBA)
Threshold Form

6. EMI Analyst™
CS114 Settings Explained
• Limit Form
• The Limit form contains information about the CS114 current limit.
• Values entered on the Limit form table are vertices of the CS114 current limit.
• Threshold Form
• The Threshold form contains CS114 injection power level. Power levels are
determined by driving current equal to the current limit through a test fixture
whose series impedance is 100 ohms.
• When the Pretest Calibration – Closed Loop Method is selected, power levels
shown on the Threshold form are injected on the cable while monitoring
induced current.
• For CS114, if induced current limit exceeds Limit form values by more than 6
dB, injected power is reduced.

7. EMI Analyst™
What is CS114?
Method CS114 is a conducted susceptibility test method specified in
MIL-STD-461D, E, F, and G.
• The basic concept is to simulate currents that will be developed on platform
cabling from electromagnetic fields generated by antenna transmissions both
on and off the platform.
• An advantage of this type of requirement is that it provides data that can be
directly related to induced current levels measured during platform-level
evaluations.
(from MIL-STD-461F, paragraph A.5.13)
This type of test is often considered as a bulk current test since current is the parameter
measured. However, it is important to note that the test signal is inductively coupled and that
Faraday's law predicts an induced voltage in a circuit loop with the resultant current flow and
voltage distribution dependent on the various impedances present.

8. EMI Analyst™
CS114 Requirements Can Be Confusing
What CS114 says:
(from paragraph 5.13.2 of MIL-STD-461F)
The EUT shall not exhibit any malfunction, degradation
of performance, or deviation from specified indications
beyond the tolerances indicated in the individual
equipment or subsystem specification, when subjected
to an injection probe drive level which has been pre-
calibrated to the appropriate current limit shown in
Figure CS114-1 and is modulated as specified below. The
appropriate limit curve in Figure CS114-1 shall be
selected from Table VI. For EUTs intended to be installed
on ships or submarines, an additional common mode
limit of 77 dBμA is applicable from 4 kHz to 1 MHz on
complete power cables (highs and returns - common
mode test). Requirements are also met if the EUT is not
susceptible at forward power levels sensed by the
directional coupler that are below those determined
during calibration provided that the actual current
induced in the cable under test is 6 dB or greater than
the calibration limit.
What CS114 Means:
1. Record the power level needed to generate
the Limit current in a standard test fixture.
2. Inject the test signal on each cable bundle
using the lesser of:
A. The recorded power level
B. Two times the limit current

9. EMI Analyst™
Pretest Calibration
(from MIL-STD-461F, pargraph 5.13.3 and 5.13.4)
1. Place the injection probe around the center conductor of
the calibration fixture.
2. Terminate one end of the calibration fixture with a 50 ohm
load and terminate the other end with an attenuator
connected to measurement receiver A.
3. Set the signal generator to 10 kHz, unmodulated.
4. Increase the applied signal until measurement receiver A
indicates the current level specified in the applicable limit is
flowing in the center conductor of the calibration fixture.
5. Record the "forward power" to the injection probe indicated
on measurement receiver B.
6. Scan the frequency band from 10 kHz to 200 MHz and
record the forward power needed to maintain the required
current amplitude.

10. EMI Analyst™
Test Procedure
(from MIL-STD-461F, paragraph 5.13.3 and 5.13.4)
1. Place the injection and monitor probes around a cable bundle interfacing with EUT connector.
2. To minimize errors, maintain the same signal circuit that was used for calibration between the attenuator at
the calibration fixture (oscilloscope, coaxial cables, bulkhead connectors, additional attenuators, etc.) and
connect the circuit to the monitor probe. Additional attenuation may be used, if necessary.
3. Locate the monitor probe 5 cm from the connector. If the overall length of the connector and backshell
exceeds 5 cm, position the monitor probe as close to the connector's backshell as possible.
4. Position the injection probe 5 cm from the monitor probe.
Perform the following procedures on each cable bundle interfacing with each electrical connector on the EUT
including complete power cables (high sides and returns). Also perform the procedures on power cables with
the power returns and chassis grounds (green wires) excluded from the cable bundle. For connectors which
include both interconnecting leads and power, perform the procedures on the entire bundle, on the power
leads (including returns and grounds) grouped separately, and on the power leads grouped with the returns
and grounds removed.
(continued on next slide)

11. EMI Analyst™
Test Procedure
(from MIL-STD-461F, paragraph 5.13.3 and 5.13.4)
1. Turn on the EUT and allow sufficient time for stabilization.
2. Susceptibility evaluation.
a. Set the signal generator to 10 kHz with 1 kHz pulse modulation, 50% duty cycle.
b. Apply the forward power level determined under 5.13.3.4b(4) to the injection probe while
monitoring the induced current.
c. Scan the required frequency range in accordance with 4.3.10.4.1 and Table III while maintaining
the forward power level at the calibration level determined under 5.13.3.4b(4), or the maximum
current level for the applicable limit, whichever is less stringent.
d. Monitor the EUT for degradation of performance during testing.
e. Whenever susceptibility is noted, determine the threshold level in accordance with 4.3.10.4.3 and
verify that it is above the applicable requirement.
f. For EUTs with redundant cabling for safety critical reasons such as multiple data buses, use
simultaneous multi-cable injection techniques.

12. EMI Analyst™
CS114 Test Method and Current Limit

13. EMI Analyst™
Calibration Fixture
(from MIL-STD-461F, paragraph A.5.13)
The calibration fixture with terminations is a 50 ohm transmission line.
Since the injection probe is around the center conductor within the
fixture, a signal is being induced in the loop formed by the center
conductor, the two 50 ohm loads, and the structure of the fixture to
which the 50 ohm loads are terminated. From a loop circuit standpoint,
the two 50 ohm loads are in series, providing a total loop impedance of
100 ohms. Because of the transmission line configuration, inductance
effects are minimized. Measurement of induced current levels is
performed by measuring a corresponding voltage across one of the 50
ohm loads. Since the 50 ohm loads are in series for the induced signal,
the total drive voltage is actually two times that being measured.
The actual current that appears on a tested cable from the pre-
calibrated drive signal depends on the loop impedance associated with
the cable and the source impedance characteristics of the drive probe
and amplifier. If the loop impedance is low, such as would often result
with an overall shielded cable, currents greater than those in the
calibration fixture will result. The maximum required current is limited
to 6 dB above the pre-calibration level.

14. EMI Analyst™
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