GE PACSystems RX7i Cpu Programmer's Reference Manual page 28

Using Parameters with UDFBs
UDFBs support up to 63 inputs and up to 64 outputs.
Each UDFB has a predefined Boolean output parameter, Y0, which the CPU sets to true upon each
invocation of the block. Y0 can be controlled by logic within the block and provides the output status
of the block.
The following table lists the TYPEs, LENGTHs, and parameter-passing mechanisms allowed for UDFB
parameters. For additional information on parameter passing, refer to Parameter Passing
Mechanisms.
Type Length
BOOL 1 to 256
BYTE 1 to 1024
INT, UINT, 1 to 512
and WORD
DINT, REAL, 1 to 256
and DWORD
LREAL 1 to 128
Function 1
block
(standard or
PACMotion)
UDFB 2 1
UDT 1 to 1024
2 A maximum of 16 input parameters can be of type UDFB.
GFK-2950C
Parameter Passing Mechanism
INPUTS: by reference, constant
reference, value, or value result.
(Default: value)
OUTPUTS: by result; except Y0,
which is by initial-value result
INPUTS: by reference, constant
reference, value, or value result.
(Default: value)
OUTPUTS: by result
INPUTS: by reference, constant
reference, value, or value result.
(Default: value)
OUTPUTS: by result
INPUTS: by reference, constant
reference, value, or value result.
(Default: value)
OUTPUTS: by result
INPUTS: by reference, constant
reference, value, or value result.
(Default: value)
OUTPUTS: by result
INPUTS: by reference, constant
reference, (Default: reference)
OUTPUTS: by result
INPUTS: by reference, constant
reference, friend
OUTPUTS: not allowed
INPUTS: by reference, constant
reference
OUTPUTS: not allowed
February 2018
Chapter 2. Program Organization
Retentiveness of Instance Data for
Parameters
Not Applicable if passed by reference,
since not stored in instance data.
Can be retentive (default) or non-
retentive for value or value result.
Retentive (default) or
Non-retentive
Retentive for value or value result.
Not applicable for reference
Retentive for value or value result.
Not applicable for reference
Retentive for value or value result.
Not applicable for reference
Retentive for value or value result.
Not applicable for reference
Not applicable since passed by
reference
Not applicable since passed by
reference
Not applicable since passed by
reference
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