  We present new CO and C^o line measurements of the compact circumnuclear disk
in the center of NGC 128 (Centaurus~A) obtained with the Herschel Space
Observatory, as well as SEST, JCMT, and APEX. The Cen A center CO ladder is
quite different from those of either star-burst galaxies or AGNs. In addition,
the relative intensity of the central Cen A [CI] emission lines is much greate
than that in any other galaxy. The CO surface brightness of the compact
circumnuclear disk (CND) is significantly higher than that of the much more
extended thin disk (ETD) in the same line of sight. Our LVG and PDR/XDR models
suggest that much of the CND gas is relatively cool (25 - 80 K) and not very
dense (~ 300 cm^{-3}) if the heating is by UV photons, although there is some
gas in both the CND and the ETD with a much higher density of ~30 000 cm^{-3}.
Finally, there is also high-excitation, high-density phase in the CND (but not
in the ETD), either in the form of an extreme PDR but more likely in the form
of an XDR. The total gas mass of the Cen A CND is 8.4 x 10^{7} M(sun),
uncertain by a factor of two. The CO-H2 conversion factor is 4 x 10^{20} K
km/s, also within a factor of two.
