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– The D20MX has 16 MB of built-in NVRAM, compared to the 512 KB of NVRAM
available in its predecessor. Subsequently, there is no need for additional memory
expansion modules.
– The firmware flash memory size in the D20MX is 128 MB, compared to the 2 MB of
its predecessor.
– The D20MX uses a Super Capacitor which allows the system clock to be saved for
14-days even after power off.
Q:
How does configuration storage work in the D20MX?
A:
The Super capacitor strictly allows the retention of the system clock time for 14-days.
At power-up, the configuration resides in the RAM. At power-down, configuration
resides in the flash. This is possible due to the seamless transaction between the RAM
and flash. This arrangement protects the D20MX configuration from being lost, even
after power-down for an indefinite period of time.
Q:
Why does the D20MX use the Vxworks Operating System instead of pSOS?
A:
Vxworks is designed for mission critical systems. It is purpose-fit, extremely robust
and fast. It is industry-focused and designed from the ground-up to be a real-time
operating system. It is the new operating system of choice for numerous embedded
systems that require a high level of robustness.
A:
Embedded systems manufacturers are moving away from the pSOS operating
system since on-going support for this operating system is very limited.
Q:
Is the D20MX hardware backward compatible?
A:
The D20MX hardware is compatible with the I/O modules installed in the field.
A:
Due to aging printed circuit board assembly and mechanical constraints, only certain
chassis from 2002 and onward can be used with a D20MX. This comprises the
following chassis:
– D20 VME chassis 500-0280 Release 08 or higher
For the VME chassis 500-0280, the zero volt cable supplied with the D20MX KIT,
must be connected from the zero volt TB2 terminal block on the 517-0225 to zero
volt on the 517-0123. Review the hardware manual for the steps involved. Part
number for the zero volt wire cable is 975-1237.
– D20 Non-VME chassis 500-0305 Release 18 or higher
Q:
Are the PCOMMON versions compatible with the D20MX?
A:
The following PCOMMON versions are compatible with the D20MX:
– P022 v3.06, v3.05 and 3.00: PCOMMON for D20C
Note: v3.06 is required if fiber optic repeaters / splitters are used.
– P010 v3.06, 3.05, 3.01 and 3.00: PCOMMON for D20A, D20S and D20K
– P087 v1.04, 1.03 and 1.02: pBOOT for D20AC
A:
Also see the PCOMMON versions compatible with the D20MX in Table 13 on page 44.
Q:
What is the recommended operating temperature range of the D20MX?
A:
The operating temperature range is 0°C to +70°C.
Note: Do not operate the D20MX above 60°C for extended periods of time as this
shortens the life of the super capacitor and reduces the backup time of the real time
clock.
APPENDIX C: FREQUENTLY ASKED QUESTIONS
GE INFORMATION
D20MX INSTRUCTION MANUAL
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