posted 03-13-2010 10:01 PM               

After several months of preparation - research, documentation, and planning - I reached a milestone this past week by having my S-IB Networks and S-IB Operations panels both wired up and connected to a Programmable Logic Controller (PLC). I wanted to share a few photos of the project thus far.

First, here's the back view of the S-IB Networks panel. The neatly-bundled white wiring is the original wiring for the panel. The wiring goes from the switches and indicators on the face of the panel to a backplane, and from there to circular connectors. My additions are the three heavy cables which branch into 120 smaller wires. I promise I'll clean this up once I am sure it all works!

Since I still consider myself to be in test mode, I made temporary connections to the backplane with quick disconnects and also to some of the Roto-Tellite indicators using ring connectors that are slipped over terminals and held on with rubber antenna caps. I did not make any modification to the original wiring, nor did I make any permanent connections to any part of the panel. That way, the panel can be returned to its original state simply by removing the temporary connectors.

Here are some connections to the backplane.

Here are a few of the connections to the Roto-Tellite enclosures for the indicator lights.

The face of the panel looks much better, I assure you!

I'm just starting now to enter the logic for driving the panel into the PLC. The switches and their associated indicators are not directly connected to each other. When you throw a switch, it registers as a program input, and then the program logic can send a corresponding output to one or more indicators. The PLC also has timers, so I will eventually integrate a timed countdown sequence that will progress appropriately - and stop if the switches aren't in their proper positions at the appropriate stage of the countdown.

Here is the Switch Selector section of the panel, showing a malfunction of the Switch Selector that has allowed two stages of the Saturn IB to be addressed by the same command.

These sections of the panel prepare the S-IB stage for a plug-drop or simulated flight test, and also prep it for the ignition sequence. The heavy switches in the Ignition section have to be pulled out and then moved into place - there's no way you can accidentally throw the switches!

What's really exciting for me now is being able to throw a switch on the Networks panel, and see the corresponding indicator illuminate on BOTH the Networks and the Operations panels.

Eventually, I hope to integrate these two panels with a countdown and range time clock. In the meanwhile, I'm having a blast bringing these panels back to life for the first time since 1975. I'll have to wear my ASTP Firing Room access badge when I'm ready for my first public demo!

posted 03-14-2010 08:44 AM               

I have not yet addressed the 8 meters on the top of the panel, which measured electrical bus voltage and battery temperature. There is also a digital counter in the Switch Selector section which I believe counted current pulses and kept track of how many commands had been issued on the Switch Selector system. The wires terminate inside the counter itself, so I can't trace it out without either cutting into a wire or breaking open the box.

Steve, I am not an electrical engineer, nor do I play one on TV! I know enough about electricity to keep from electrocuting myself. I'm sure a professional engineer would make much shorter work of this than I am, as I am feeling my way through the panel with a volt-ohmmeter and patience. This is truly an educational experience for me in many regards.

posted 03-16-2010 01:00 PM               

But yes, the hand-tied ribbons around the wire bundles are just incredible. There's no way I will ever cut into them.