PLC's on space shuttle

Jiri Toman said:
It seems that the heaters used to prevent ice build up on the launch pad are controlled by PLC's. I wonder which ones.

The most likely candidate is PLC-5.
I've been told that there were redundant Allen Bradley redundant something-or-others controlling parts of the shuttle launch pad.

Government funding = American products (Allen Bradley).
Mission critical = well aged/tested product line.

AK
 
I know that PLC-5's were used in conjuction with the Space Shuttle launch (ground) controls, I just don't know about the on-board systems.
 
I read somewhere (years ago) that an Apple II took a ride and operated flawlessly. The Russians also used Apple IIs on some of their fighters for wepons systems and avionics.

I know for sure that the Space Shuttle launch pad elevators use GE 90-30s.
 
mgvol said:
I know that PLC-5's were used in conjuction with the Space Shuttle launch (ground) controls, I just don't know about the on-board systems.

The on-board stuff is mostly micro-processor based, I think. I read somewhere that Pentium (Pentium 1) or similar processors had just recently been given the seal of approval.

Why fly a PLC? That bulky case is going to affect your gas milage.

AK
 
I know that the Saturn V flew with DEC PDP-8 computers and somewhere I heard that the first few flights of Enterpirse (Atmospheric glide tests, Enterprise never orbited) and Columbia used PDP11s, but were quickly replaced when newer avionics packages were added. But that could have been just hearsay.

I dont think the size of a PLC would be a problem. Shuttle systems need to be able to withstand the rigors of launch and reentry. PLCs are power hogs however, which is a problem on the shuttle. However, Rockwell is the contractor that built the shuttle, so its possible.
 
Alaric said:
I dont think the size of a PLC would be a problem.

Weight is always an issue. I imagine anything on the shuttle itself is probably not recogocnizable next to an off-the-shelf model.

Rockwell may have built the shuttle (really???), but NASA (one would assume) wrote the specs. With NASA being the end customer and the engineers, I imagine they didn't brand "PLC or DEATH" on the contract before weighing the options. There was no customer demand for a specific product, so they could've picked anything they wanted for controls.

AK
 
akreel said:
Weight is always an issue. I imagine anything on the shuttle itself is probably not recogocnizable next to an off-the-shelf model.

AK

Surely weight isn't an issue in space...

:ROFLMAO:

Paulus
 
I heard from some A-B types at a trade show that a PLC-2/30 runs the launch sequence and that a PLC-3 controls the tractor used to haul the shuttle from the hangar to the pad. This was two years ago.
 
An AB you must be joking....
Think redundancy.....
TMR.......
It's a Triplex!
 
I thought most of the programs and controls are done on
ICs and compact on PCBs. So they will not get very affected by vibrations and some other inconveniences. Just some thoughts.;)

regards
Sherine T.
 

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