Campbell Scientific CSM1 Card Storage Module - Manual (Page 18)

CSM1 Card Storage Module
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does not move its internal pointers and consequently the CR10 does not get
confirmation of successful data transfer at the end of the transmission; thus it
does not move its SPTR. This means that no data is lost as the CR10 will send
the whole block again. However, for a large block transmission from the
datalogger, e.g. a manual dump of the whole memory, it can appear that the
card suddenly becomes full without storing any data from the datalogger.
Subsequent attempts at storing small blocks of data to the card are
unsuccessful, as the card is marked as full and the module does not wake up.
This method of operation has been implemented to minimize power
consumption in remote applications.
A similar phenomenon will be apparent when writing large programs or text
files to a card that is almost full.
Once a card has been marked as full it cannot store any more data until the
'full' flag is reset. There are two mechanisms you can use to do this:
1) By erasing and resetting the card, after extracting your data.
2) By disconnecting and reconnecting the CSM1 to the datalogger. If the
card is plugged in when the CSM1 powers up, the CSM1 will warn you
that the card has previously been marked as being 'full' by flashing the
status LED seven times. The CSM1 will then reset the card's internal
'full' flag to enable further attempts at data storage to be made. If there is
any free space in the card, it can then be used to collect smaller blocks of
data. However, if it is reconnected to the same CR10, as in the example
above, which still has too large a block of uncollected data, collection will
not be successful. If too large a block is sent again, the card will be
marked as full again.
7. Telecommunications
Campbell Scientific's CSMCOM program is recommended for communicating
with the CSM1 when using IBM-compatible PCs under the DOS operating
system. However, any computer can communicate with the CSM1 via an
RS232 interface.
This section describes how to connect and establish communication with the
CSM1 when not using CSMCOM. It also describes the telecommunications
commands to which the CSM1 responds. These can be used when writing your
own software, or when using the terminal emulator mode of CSMCOM.
7.1 Connecting the CSM1 to Non-IBM Computers
The SC532(A) is normally used to connect the CSM1 to the serial port of a
computer. The SC532(A) is wired as a DCE, RS232 device. Please refer to the
SC532(A) manual and your computer manual to ensure correct connection of
the two.
To wake up the CSM1 into telecommunications mode, two handshaking lines
(lines 4 and 20) on the SC532(A) must be taken from the MARK (negative) to
SPACE (positive) state and held high during communications.