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RTCA SC-135 and EUROCAE WG-14
Change Proposal Form
(One major comment per form.)
(Shaded blocks for committee use only.)
SC-135/WG-14 Paper Number:
Date:
DO-160F/ED-14F Section: 22
Rev G #102
03/10/2009
AE2_G_P013
Author’s Name, Affiliation, and E-mail:
Paragraph:
Page:
Terry Milks, Rockwell Collins
22.5.1.1
22-10
[email protected]
Summary of Change (25 words or less):
Eliminate the resistor method for pin injection generator calibration
Proposal Page Number:
1 of 5
SC-135/ED-14 Change Proposal Form Rev G
Reason for Change (Justification):
The current pin injection calibration procedure does not require the generator to produce the Isc
level if using the resistor method of impedance verification. In addition, the resistor method
actually allows a generator that produces an Isc greater than +10% from the Isc in Table 22-2. For
example:
If you were performing a waveform 4, level 3 calibration, you would set the generator to produce
a Voc of 300 volts and then place a 5 ohm resistor across the generator output and verify the
voltage measurement across the resistor is one half the Voc (+10%). If the Voc reduces to 135
volts, this would be within the +10% tolerance. In this case the generator impedance is a little
over 6.1 ohms which would result in a short circuit current of approximately 49 amps. The
proposed change will require the generator to produce at least the Isc at the generator setting
determined during calibration. The previous method also did not account for any tolerance of the
resistor value used which could result in even greater variation from the intended calibration
parameters.
Proposal Page Number:
2 of 5
SC-135/ED-14 Change Proposal Form Rev G
Revise From:
22.5.1.1
Procedures - Generator Calibration
Calibration set-up to be as shown in Figure 22-10. For the pin injection tests with power on, in
order to avoid shorting EUT currents through the generator low source impedances, a current
blocking component should be included at the output of the pin test generator. This current
blocking component is to be included as part of the calibration setup as shown in Figure 2210.
When testing power pins with external power applied, the calibration setup of Figure 22-11 or
Figure 22-12 would be applicable. In these setups, a means must be provided to bypass the
power supply impedances to ensure that the transient waveform can be achieved at the
calibration point. This bypass circuit also serves to protect the power supply. Note that power
should not be applied while performing the following calibration procedure.
a.
Adjust the transient generator such that the applicable open circuit voltage (Voc)
waveform parameters identified in Figure 22-4 to Figure 22-6 and level of Table 22-2 are
attained at the calibration point shown in Figure 22-10, Figure 22-11 or Figure 22-12 as
applicable.
b.
Record the Voc, and verify that the applicable waveform parameters have been satisfied.
Note the waveform polarity.
c.
Record the generator setting so that the test level can be repeated during testing.
d.
As illustrated in Figure 22-10, Figure 22-11 or Figure 22-12, connect a non-inductive
resistor equal in value to the test waveform source impedance
e.
With the generator set as previously determined, record the voltage across the noninductive resistor and verify the voltage waveshape parameters and that the amplitude
reduces to one half of Voc (10%). This verifies that the generator source impedance is
correct. Alternatively, the generator short circuit current waveshape and amplitude can
also be verified by recording the short circuit current (Isc) for the previously determined
generator setting. In either case, the general waveshape shall be retained.
f.
Remove the non-inductive resistor added in step d.
Proposal Page Number:
3 of 5
SC-135/ED-14 Change Proposal Form Rev G
Revise To:
22.5.1.1
Procedures - Generator Calibration
Calibration set-up to be as shown in Figure 22-10. For the pin injection tests with power on, in
order to avoid shorting EUT currents through the generator low source impedances, a current
blocking component should be included at the output of the pin test generator. This current
blocking component is to be included as part of the calibration setup as shown in Figure 2210.
When testing power pins with external power applied, the calibration setup of Figure 22-11 or
Figure 22-12 would be applicable. In these setups, a means must be provided to bypass the
power supply impedances to ensure that the transient waveform can be achieved at the
calibration point. This bypass circuit also serves to protect the power supply. Note that power
should not be applied while performing the following calibration procedure.
a.
b.
Adjust the transient generator such that the applicable open circuit voltage (Voc) and
short circuit current (Isc) waveform parameters identified in Figure 22-4 to Figure 22-6
and level of Table 22-2 are attained within specified tolerances at the calibration point
shown in Figure 22-10, Figure 22-11 or Figure 22-12 as applicable.
Record the Isc and Voc waveforms and levels, waveform polarity and the generator
setting so the test level can be repeated during testing.
Proposal Page Number:
4 of 5
SC-135/ED-14 Change Proposal Form Rev G
As Modified Text:
X
Accepted As Written
Withdrawn
Accepted As Modified
Rejected
Deferred
Other
Rejection Reason / Comments:
Proposal Deferred To:
RTCA SC-135 Concurrence
Proposal Disposition By:
SC135
EUROCAE WG-14 Concurrence
Date:
3/19/09
Proposal Page Number:
5 of 5
SC-135/ED-14 Change Proposal Form Rev G