The auxiliary channel test’s primary function is to query
the DCB and report specific data-such as detector temperature, power
supply voltages, board temperatures, and KV/mA readings-as a function
of the DCB. With the exception of the KV/mA channel sub-test, this
test uses basic firmware routines to communicate and query the DCB.
It does not use the Scan Acquisition process that DDC uses. The reason
is that if the DAS fails power-up diagnostics, the error is reported
to software and scanning is prevented, either in applications or Diagnostic
Data Collection (DDC). This “tool” allows the user to
query the DCB and read the supply voltages, or detector / board temperatures
“real-time”. The only exception is if the 48 vdc digital
supply is so low as to not let the DCB function at all, or if the
DCB cannot communicate with the ORP.
Figure 1. Auxiliary Channels Defaults
1 Current Detector Heater Temperature and Spec.
The detector temperature is measured by the DCB as is reported
in one of the auxiliary channels. The reported value is in the format
shown in Table 1.
2 Power Supply Voltages
DCB circuitry measures all DAS power supplies and reports in
the auxiliary channels in the form of voltages. The list of supplies
are show in Table 2.
These Power Supply and temperature data can be viewed in the
below file:
The normal operating temperature range of the DAS is between
25° - 40° Celsius. If the temperature reaches 55° C, then
a warning error message posts to the Status Area of the ExamRx Desktop
and associated error message in the error log. If the temperature
reaches 62° C, then the DAS will report an over-temperature fault,
and will prevent further scanning until the DAS cools and is reset.
DAS Tools shall query-real-time-the DAS converter board temperature,
compare it to spec, and display test output as shown in Table 2
4 KV / mA Channels
These auxiliary channels report the actual KV and mA signals
as read from the generator (KV and mA control boards). Since this
requires x-ray, this test is not part of the auto-mode, but it can
be initiated in the manual-test mode with operator intervention. You
must push the Scan Enable push-button to initiate x-ray. All x-ray
safe guards are in place, which terminate x-ray in the event of a
system failure, tube cooling limitations, or exposure time limitations.
The test takes several scans at selected techniques, and the
DCB measured KV and mA signals are compared to the selected techniques,
as well as to the system reported measured signals. If the DCB reported
signals do not match the system reported output, then this test will
fail with the following error message:
DCB board measured KV (or mA) differs than system measured
KV (or mA) reading.
If the reading matches the system reported values, but is outside
the system spec for selected technique, then the test should fail,
but would indicate the DCB aux. channel is working correctly, but
KV (or mA) is out of spec. Refer to HV set-up/Troubleshooting.
