Siemens SIMATIC LOGO! CMR2020 Operating Instructions Manual page 86

Operation
Reading / writing "current values" via the BM variables memory
"Current values" (e.g. flags, counters) are read and written only via the BM variables
memory.
Note
Current values: Reading/writing only via the BM variables memory
For reasons of security, setting or reading of current values of the function blocks of the BM
(e.g. counters) is possible only via their address in the BM variables memory.
All components of the LOGO! switching program must therefore initially be transferred to the
BM-internal variables memory using the "LOGO! Soft Comfort" program. Only then are the
components visible with their start addresses and length (type) for the CMR in the BM
variables memory.
Address and type (<address>,<data type>) are parameters that need to be specified in the
relevant SMS message commands (Page 122).
Note
Setting an individual bit
To set an individual bit, the data types available must be used.
<data type>"BYTE" in the variables memory: Length: 1
<data type>"WORD" in the variables memory: Length: 2
<data type>"DWORD" in the variables
memory:
Note
Access only to the first 128 bytes of the VM (variables memory)
In LOGO!Soft Comfort, the VM goes up to address 850. Via the CMR, however, only the first
128 bytes can be accessed.
For security reasons the address in the VM memory can only be read or written using SMS if
the address was created earlier as a signal using the WBM.
86
Length: 4
LOGO! CMR2020 / LOGO! CMR2040
Operating Instructions, 09/2014, C79000-G8976-C356-01