4 Wiring with 800
4.7 Working with function blocks
Control Relay easy800 11/11 MN04902001Z-EN www.eaton.com 133
Depending on the display selected the function block is shown with the
actual values and the result, or with the set operands and constants.
Press the ALT pushbutton if you wish to switch from operand to actual value
display or vice versa during the check of the standard function block.
▶ Press the ALT pushbutton again (see also the following note).
Tips for working with function blocks
• Current actual values are deleted when you switch off the power supply
or switch the easy800 device to STOP mode. Exception: Retentive data
keeps its state (￫ section 8.2.6, “Retentive data storage”, page 308,).
The most recent actual values are transferred to the operands every
cycle. The data function block is an exception.
• If you want to prevent other people from modifying the parameters of the
function blocks, change the access enable symbol from “+“ to “–“ when
creating the circuit diagram and setting parameters. You can then protect
the circuit diagram with a password.
• As every function block in the function block list takes up memory, even
if it is no longer being used and has been deleted in the circuit diagram,
you should clear it occasionally. Check the function block diagram for any
function blocks that are no longer required and delete them,
￫ Section 4.7.5, “Deleting function blocks“, Page 132.
• The function blocks are designed so that an output value of a function
block can be assigned directly with an input of another function block.
The 32-bit data format is used automatically. This also enables the
transfer of negative values.
CAUTION
The following applies to RUN mode: A easy800 device
processes the function block after a pass through the circuit
diagram. This takes the last status of the coils into account.
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