Campbell Scientific SM4M/SM16M Storage Modules - Manual (Page 30)

Section 5. Data Retrieval
5-4
5.3.2 Connection Via CR500/510, CR10/10X or CR23X
Make the connections (see Figure 5-2 or 5-3) and establish communications
with the datalogger. Send the command ‘xM,CR’ to the datalogger (where x is
the Storage Module address 1...8). If the connections are correctly made and
the Storage Module is properly addressed, it will send back ‘CR, LF, %.’ If the
attempt to establish communications fails, the datalogger will return ‘*’.
Once the ‘%’ is received, the Storage Module telecommunications commands
(see Appendix B) may be used. SMS can be used when the connection to the
datalogger is through the SC32A Optically Isolated RS232 Interface as shown
in Figure 5-3.