GE 90-30 PLC Series Installation And Hardware Manual page 123

5
Table 5-5. Range and Size of User References for CPU Models 350 through 374
Application Program Compatibility
Programs that have been developed on Series 90-30 CPUs 311-341 will automatically be
translated by the programming software when used on CPUs 350-374. Programs created or
translated for CPUs 350-374 will automatically be translated when used with CPUs 311-341;
however, be aware that some CPUs support features, such as floating-point math or larger memory
sizes, that are not supported by other CPUs. In those cases, attempting to load a program to a CPU
not supporting one or more of the programmed or configured features will result in an error.
However, in some cases it may be possible to edit the program and configuration to make them
compatible with the targeted CPU.
CPU Time-of-Day (TOD) Clock Accuracy
The accuracy of the Series 90-30 time-of-day clock is ?9 seconds per day across the rated
operating temperature range of 0-60°C. The accuracy is relatively stable at any fixed temperature.
For applications that require greater accuracy, the following suggestions are furnished:
5-12 Series 90-30 PLC Installation and Hardware Manual – August 2002
Reference Type
Maximum User memory*
Discrete inputs
Discrete outputs
Discrete globals
Internal coils
Temporary coils
System status references
System register references
Analog inputs
Analog outputs
System registers**
* Depends on user-defined value(s) of configurable memory.
** May be viewed only with a Hand-Held Programmer (see the Hand-Held Programmer User's
Manual, GFK-0402) ; may not be referenced in a user's logic program.
For an installation where the temperature of the CPU is stable, measure the amount of time
drift for a 24 hour period, then program a "correction" factor into the ladder program to add or
subtract seconds periodically to keep the CPU time accurate. The instruction to use in this
case is Service Request #7, "Change/Read Time-of-Day Clock." At the appropriate time, a
Model 350/351/352/360/363/364/374 CPU
Reference Range
Not applicable 240K Bytes, configurable
(CPU350: 32K Bytes, fixed)
%I0001 – %I2048 2048 bits
%Q0001 – %Q2048 2048 bits
%G0001 – %G1280 1280 bits
%M0001 – %M4096 4096 bits
%T0001 – %T0256 256 bits
%S0001 – %S0032 32 bits
%SA001 – %SA032 32 bits
%SB001 – %SB032 32 bits
%SC001 – %SC032 32 bits
%R0001 – %R32640* 128 – 32,640 words, configurable.
(CPU350: 9999 words, fixed,)
%AI001– %AI32640* 128 – 32,640 words, configurable.
(CPU350: 2048 words, fixed)
%AQ001–%AQ32640*
128 – 32,640 words, configurable.
(CPU350: 512 words, fixed)
%SR001 – %SR028 28 words
Size
GFK-0356Q