Siemens SINUMERIK 840D sl Function Manual page 331

Data, for which no unique physical units are defined, is not converted automatically.
This includes:
● R parameters
● GUDs (Global User Data)
● LUDs (Local User Data)
● PUDs (Program global User Data)
● Analog inputs/outputs
● Data exchange via FC21
In this case, the user is requested to take into account the currently valid system of units:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC
The current system of units setting can be read using PLC interface signal:
DB10 DBX107.7 (inch system)
Using the signal:
DB10 DBB71 (change counter, system of units inch/metric)
the "system of units change counter" can be read out
● The system of units for sag compensation is configured using:
MD32711 $MA_CEC_SCALING_SYSTEM_METRIC
References:
Function Manual Extended Functions; Compensations (K3)
● The system of units for positional data of the indexing axis tables and switching points for
software cams is configured in machine data element:
MD10270 $MN_POS_TAB_SCALING_SYSTEM.
References:
Function Manual, Extended Functions; Software Cams, Limit Switching Signals (N3) /
Indexing Axes (T1)
User tool data
The physical units for user-defined tool and tool cutting edge data can be set in the following
machine data:
● MD10290 $MN_CC_TDA_PARAM_UNIT
● MD10292 $MN_CC_TOA_PARAM_UNIT
When the system of units is switched over, all length-related tool data is converted to the new
system of units.
Reference point
The reference point is retained. It is not necessary to repeat referencing.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
G2: Velocities, setpoint / actual value systems, closed-loop control
7.3 Metric/inch measuring system
331