gbt@sequoia.cray.com (Greg Titus) (12/14/90)
In article <MCDANIEL.90Dec11145809@dolphin.adi.com> mcdaniel@adi.com (Tim McDaniel) writes: >In article <1990Dec11.044056.5418@jato.jpl.nasa.gov> >baalke@mars.jpl.nasa.gov (Ron Baalke) writes: >> A NO-OP command was sent on November 30 to reset the Command Loss >> Timer to 96 hours. > >It's not really a NO-OP then, is it? A NO-OP with side effects. Gak. Every time the spacecraft receives a message from Earth, the Command Loss Timer (CLT) is set to its timeout value and begins ticking. (Presumably there is some command which sets this timeout value.) If the CLT ever ticks down to zero, the spacecraft assumes that contact with Earth has been lost, and starts looking for it. The NO-OP is really a NO-OP. It doesn't do anything. The mere fact of its reception is what resets the CLT. This is not a side effect of the NO-OP, though. All commands received by the spacecraft reset the CLT. Somebody (Ron?) please tell me if my explanation is incorrect. greg -- -------------------------------------------------------------- Greg Titus (gbt@zia.cray.com) Compiler Group (Ada) Cray Research, Inc. Santa Fe, NM Opinions expressed herein (such as they are) are purely my own.