Testing or debugging a MIL-STD-1553 terminal or system is a not a trivial task. There are a large number of variables to consider: timing, message formats, mode commands, status word bits, and coupling methodology. In addition, history has shown that different component manufacturers and designers have made different interpretations regarding the standard, thereby introducing products that implement the same function quite differently. Many 1553 test tools today require an in-depth knowledge of 1553 in order to effectively test and debug – making it a challenge for engineers who are less familiar with the protocol specifics to troubleshoot a system.
On top of that, engineers may not always have the necessary tools on hand to efficiently conduct an electrical analysis with a scope and diagnose an issue. At Abaco, we’ve witnessed a variety of homegrown MacGyver solutions that our customers have employed to circumvent this challenge. We’ve seen “T” couplers with paper clips shoved in to gain access, as well as cables stripped to bare wires so the differential pair can be probed on a scope using two channels in differential mode (or using a differential probe, if available). Scope-based 1553 tools exist, but are often expensive and limited in their functionality by the rudimentary user interface on the scope front panel control. The challenge of using existing tools, as well as tight project timelines, often necessitate workarounds such as the examples described above. These solutions generate questionable results and often create additional issues.
Three tools in one
To help address the challenges presented by many of the existing 1553 scope analysis tools and the steep protocol learning curve, Abaco created the BT3-USB-MON. This software and hardware bundle combines three tools into one easy-to-use product: 1553 visualization, analysis and recording with user-friendly GUI BusTools/1553-BM (bus monitor only); USB-based 1553 monitoring hardware; and an integrated differential scope output for electrical analysis - all available at an accessible price point.
The BT3-USB-MON can be easily inserted anywhere in the 1553 signal chain, directly on the bus or on a stub, using standard twin-ax cables and couplers. While it does not require a scope for operation, the BT3-USB-MON provides single ended 10:1 BNC outputs for both the A and B buses which may be easily connected to any scope for viewing of the 1553 waveform if desired. Additionally, an output is provided which can be configured through BusTools to provide scope triggering under very specific configurable bus traffic conditions, making it easier to capture elusive bus anomalies.
The software helps users overcome some of the 1553 learning curve by providing the capability to quickly and intuitively monitor and drill-down on bus traffic without requiring extensive 1553 protocol expertise. If a user’s needs evolve to require BC and/or RT functionality down the road, there is a clear migration path to the full version of BusTools/1553 and the multi-function R15-USB to meet those needs.
With its combination of functionality, ease of use and affordability, the BT3-USB-MON is an essential analysis tool for any engineer who needs to test or debug a 1553 network.