Reading From Plc-I/Os - Siemens SINUMERIK 840D sl Function Manual

Extended functions

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A4: Digital and analog NC I/O for SINUMERIK 840D sl

2.3 Direct I/O access via PLC

● Update cycle: I/O input data → system variables = 3 * interpolator cycle= 3 * 12 ms = 36 ms

MD10398 $MN_PLCIO_OUT_UPDATE_TIME = 3 * 0.012 = 0.036

● Data format: Big endian

MD10399 $MN_PLCIO_TYPE_REPRESENTATION = 1

The transfer of the system data to the PLC I/O is not performed until the PLC has detected the

PROFIBUS/PROFINET I/O error-free after the control startup. The transfer is then performed

in every third interpolation cycle.

Writing the NC I/O to synchronized actions with R parameters:

Program code

ID=1 WHENEVER TRUE DO $A_PBB_OUT[0]=R10

ID=2 WHEN $AA_IW[x] >= 5 DO $A_PBW_OUT[1]=R11

Addressing example: $PBW_OUT[ 1 ] = R11

Reading from PLC-I/Os

Specifications

● Decimal logical addresses of the input data to be read within the PLC I/O

– 420: 2-byte integer value

– 422: 4-byte integer value

– 426: 4-byte real value

– 430: 1-byte integer value

● The input data should be stored in a part program in the R parameters R1 - R4.

● In order to only slow down the execution of the PLC user program (OB1) slightly, the update

cycle for read access should be 3-times the interpolator cycle of 12 ms.

; 1-byte integer value

; 2-byte integer value

Function Manual, 10/2015, 6FC5397-1BP40-5BA3

Extended Functions

Sinumerik 828d