***DRAFT DOCUMENT***
Wednesday, February 19, 1997
This document describes the tests which are performed on the various SVX III data acquisition system modules. The focus of this document is to differentiate between module-level (board checkout) tests and system- or subsystem-level tests. The following definitions are assumed to apply throughout this document:
• A module-level test is one which exercises the internal features of a given PC board and does not require connection to any other board of the system to function. A module-level test may involve the use of external signal generators or other modules not part of the final system. Module-level tests usually require numerous cabling changes to perform and are not suitable for use in the field. A module-level test, upon receipt of error, attempts to isolate the error to a particular component or group of components.
• A subrack-level test is one which exercises the interconnection between Modules which share the same backplane. A subrack-level test presumes that all Modules involved have passed their module-level test prior to the running of a subrack-level test. Upon receipt of error a subrack-level test attempts to isolate the error to a particular module, but no farther.
• A subsystem-level test exercises the interconnection between subracks, or the interconnection between physically disparate modules. A subsystem test presumes that all modules and subracks involved have previously passed their respective lower-level tests prior to the subsystem test. Upon receipt of error, a subsystem test attempts to isolate the fault to the module level. Subsystem-level tests are used with a fixed cable plant and cannot require any cabling changes.
• A system-level test exercises the entire system, including all subsystems. Upon receipt of error a system test attempts to isolate the problem to the subsystem or subrack level, but no farther. System-level tests are intended for the final cabling setup and cannot require cabling changes.
A test methodology must not only include the various printed circuit boards within the system but also the interconnections between those boards. A system constructed of perfectly functioning boards but bad cables will fail just as thoroughly as one which has good cables but bad boards. The subsystem and system tests should be designed such that cabling errors may be differentiated from module or subrack errors. To this end, Figure 1 shows the generic architecture of the SVX data acquisition system and names the various devices and cables present.
Various types of software are written by different personnel. It is more appropriate for the design engineer or the technician to code the module-level tests as only they have the detailed knowledge at the bit level required. Computer professionals are more suited to the subsystem and system test programs which require a knowledge of how various modules must work together. Figure 2 shows the assumed test flow from module-level to system diagnostics and indicates which tests are likely to be written by the different people.
This document describes the module-level and subrack-level tests being developed in order to more fully define the requirements of the subsystem and system test software. Note that obvious tests such as "does the bus interface work" or "can the XX memory be written to and read back" are omitted. Only tests which exercise specific architectural features of modules are included.
