GE Series 90-30 PLC

5-12 Series 90-30 PLC Installation and Hardware Manual – August 2002 GFK-0356Q
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Table 5-5. Range and Size of User References for CPU Models 350 through 374
Reference Type Model 350/351/352/360/363/364/374 CPU
Reference Range Size
Maximum User memory* Not applicable 240K Bytes, configurable
(CPU350: 32K Bytes, fixed)
Discrete inputs %I0001 – %I2048 2048 bits
Discrete outputs %Q0001 – %Q2048 2048 bits
Discrete globals %G0001 – %G1280 1280 bits
Internal coils %M0001 – %M4096 4096 bits
Temporary coils %T0001 – %T0256 256 bits
System status references %S0001 – %S0032 32 bits
%SA001 – %SA032 32 bits
%SB001 – %SB032 32 bits
%SC001 – %SC032 32 bits
System register references %R0001 – %R32640* 128 – 32,640 words, configurable.
(CPU350: 9999 words, fixed,)
Analog inputs %AI001– %AI32640* 128 – 32,640 words, configurable.
(CPU350: 2048 words, fixed)
Analog outputs
%AQ001–%AQ32640*
128 – 32,640 words, configurable.
(CPU350: 512 words, fixed)
System registers** %SR001 – %SR028 28 words
* 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.
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
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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:
■ 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