Campbell Hausfeld SM4M - Manual (Page 16)

SM4M/SM16M Storage Module User Guide
2-2
the data transfer. If the execution interval is less than two minutes, the data
transfer will be interrupted and will take longer to complete.
Be sure to complete the data transfer before making any
changes in the datalogger program. Changing a program and
then compiling it will advance the datalogger’s Storage Module
Pointer to the position of the DSP. If this is done before
connecting the Storage Module to allow the datalogger to
transfer the data, the old data will
not be automatically
transferred to the Storage Module. Also, the Instruction 96
data transfer will not take place while the datalogger is in
communication with another device, e.g. a computer or an
active CR10KD.
To be certain that the SM has been connected during an execution of Instruction
96, you can observe the green “WRITE” LED of the SM which indicates data is
being stored in the module. Connect the SM to the datalogger and wait for the
LED to light. When the LED goes off, data transfer is complete and the SM can be
disconnected.
To avoid data loss, data must be retrieved before the datalogger’s ring memory
wraps around and begins to write over the oldest data.
2.1.1 Multiple Storage Modules with the CR500/510, CR10/10X or
CR23X
These dataloggers use synchronous addressing to communicate with multiple
peripherals. The CR23X must have OS1.7 or later to work with multiple modules.
Up to four SM4M/SM16M Storage Modules can be connected reliably to a single
datalogger. Each is assigned an address, 1 to 8. Addresses are assigned in the *9
Mode (command 10), using SMS or in the Telecommunications Command State
(the L command). These are discussed in the datalogger manuals and Appendix B
respectively. The default Storage Module address on reset (as sent from the
factory) is #1. This will be sufficient for most users.
While eight Storage Modules can be addressed,
communication may be unreliable if more than four SM4M or
SM16M modules are connected to a datalogger. Contact
Campbell Scientific if you need to connect more than four
modules.
At a given time, only one Storage Module will accept commands directed to SM
#1. If there is no Storage Module with address #1, the Storage Module with the
lowest numbered address will accept the commands sent to SM #1. Commands
directed to addresses other than #1 can be accepted only by the SM with the
correct address. Do not connect Storage Modules with the same address to a
datalogger at the same time.
If only one Storage Module is used with the datalogger, its address should be #1.
When multiple Storage Modules are used in a datalogger system, each should be
assigned its own address and set to Fill and Stop. Instruction 96 is used in the
datalogger program to send data to Storage Module address #1. The lowest
numbered Storage Module will fill up first, followed by the next lowest address,
and so on. Alternatively, data can be sent to specific Storage Modules via direct
addressing by the datalogger (using a separate Instruction 96 for each SM).
CAUTION
CAUTION