Description
(Original Document)
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Function description
The function block D_PRE is used for Monitoring process requirements.
Process requirements are process characteristics that are absolutely necessary for the operation of the machine or system (e.g. coolant, emergency stop). General requirements are for example, requirements for machine operating modes or basic settings.
The absence of such requirements is monitored. The monitoring is carried out cyclically. The activation of the diagnostics and thereby the distribution of the cycle load can be achieved through the enable signal ED.
If more than one process requirement should be monitored simultaneously, the monitoring must be carried out with a pre-enabled AND block, whose output must be connected to the IN input of the D_PRE EFB.
NOTE: Do not use diagnostic EFBs in DFBs.
EN and ENO can be configured as additional parameters.
Representation in FBD
Representation:
Representation in LD
Representation:
Representation in IL
Representation: 
CAL D_PRE_Instance (ED:=EnableDiagnosis,
    DTIME:=ToleranceTime, IN:=ProcessRequirement,
    ERR=>ErrorFlag)
Representation in ST
Representation: 
D_PRE_Instance (ED:=EnableDiagnosis,
    DTIME:=ToleranceTime, IN:=ProcessRequirement,
    ERR=>ErrorFlag) ;
Description of parameters
Description of the input parameters:
Parameter
Data type
Meaning
ED
BOOL
Enable diagnostics
DTIME
TIME
Tolerance time
IN
BOOL
Process requirement
Description of the output parameters:
Parameter
Data type
Meaning
ERR
BOOL
Error message; 0: no error; 1: Error
Public variables
Description of the public variables:
Parameter
Data type
Meaning
AREA_NR
BYTE
Automation area to be monitored.
This byte specifies which area will be monitored by the diagnostics EFB.
It is advisable to assign the numbers according to the functional modules.
Values: 0 ... 15. The standard value is 0.
Example:
  • Cutting: No. 1
  • Milling: No. 2
  • Thread cutting: No. 3
In the example AREA_NR must have the value 1, 2 or 3, so that they can recognize the error affected area.
OP_CTRL
BOOL
This bit specifies whether a diagnostic event will request a user acknowledgement.
  • 0: no user acknowledgement required
  • 1: user acknowledgement required
The standard value is 0.