EGU limits have a precision and range. The precision is the number of digits after the decimal point. The range is the span of values. For example, the default range for blocks is 0 to 100.
Changing the EGU Limit Precision
You can change the EGU limits' precision by editing the High Limit and Low Limit fields. When you change the precision, Database Manager modifies all references to the current block throughout the database. For example, if you create an Analog Input block with EGU limits of 0.0 to 100.0 and then change the precision to 0.00 to 100.00, Database Manager searches the database for all references to this block and makes the appropriate changes. In this case, a Program block that contains the following step:
SETOUT AI1 50.0
is adjusted to read:
SETOUT AI1 50.00
Changing the EGU Limit Range
To change the EGU limits' range, you must change all references to this block manually. For example, if you create an Analog Input block with limits of 0.0 to 100.0 and then change the range to 0.0 to 700.0, all references to this block's EGU limits are unaffected until you edit them. In this case, assume you have a Program block that outputs a value equal to half of this block's original range, as shown below:
SETOUT AI1 50.0
You must modify this Program block's SETOUT statement to reflect the new range, as shown below:
SETOUT AI1 350.0
EGU Limit Formats
Database Manager accommodates the EGU limit formats listed in the table Available EGU Limits. Each format is accurate to six digits. Because of compiler limitations, round-off errors may occur in the seventh digit. The following figure shows sample values and their accuracy.
NOTE: Refer to your I/O driver manual for additional integer ranges supported by your equipment.
