Campbell Scientific SM192/SM716 Storage Modules - Manual (Page 11)

SECTION 2. STORING DATA FROM CR10, 21X, AND CR7
2-2
CAUTION: 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, the user
can:
1. Leave the SM connected longer than
the execution interval of the Program
Table that includes Instruction 96,
or
2. Use the SC90 9 pin Serial Line Monitor.
The SC90 contains an LED which lights
during data transmission. The user
connects the SM to the datalogger with
the SC90 on the line and waits 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
CR10
The CR10 uses synchronous addressing to
communicate with multiple peripherals (CR10
Manual, Sections 6.2 and 6.6). Up to 8 Storage
Modules can be connected to a single CR10.
Each is assigned an address, 1 through 8.
Addresses are assigned in the *9 Mode
(Command 10), or in the Telecommunications
Command State (the L Command). These are
discussed in Appendixes A and D of this
manual, respectively. The default Storage
Module address on reset (as sent from the
factory) is #1. This will be sufficient for most
users.
At a given time, only one Storage Module will
execute commands directed to SM #1. If there
is no Storage Module with address #1, the
Storage Module with the lowest numbered
address will execute the commands sent to SM
#1. Commands directed to addresses other
than #1 can be executed ONLY by the SM with
the correct address. Do NOT connect Storage
Modules with the same address to a CR10 at
the same time.
If only one Storage Module is used with the
CR10, its address should be #1. When multiple
Storage Modules are used in a CR10 system,
each should be assigned its own address and
set to Fill and Stop. Instruction 96 is used in the
CR10 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 CR10 (using a
separate Instruction 96 for each SM).
Instruction 96 can be entered two or more times
in a program to sort data to specific Storage
Modules. Three important considerations are:
1. All Storage Modules to be used must be
connected to the CR10 with SC12
cables.
2. Time must be allowed between the
execution of multiple 96 commands to
Storage Modules. Add 5 msec to the
time it takes to store the number of
bytes to be transmitted (1 msec per
byte) before executing the next
Instruction 96 which addresses a
different Storage Module.
3. Use of the keyboard or
telecommunications during the
execution of the Instruction 96 may
backlog the data to be sent to the
Storage Modules. In this event, during
the next execution of Instruction 96 all
backlogged data will be sent to the
Storage Module addressed in that
instruction.