Specifications

OPERATIONS
Page 72 MRC-565 Packet Data Radio Operations & Maintenance
The MRC-565 limits the amount of data read from the CR10X to prevent overflowing its’
transmit memory queue. Each time a group is read, the available memory is checked, and if it
goes below 600 Queue blocks, then the MRC-565 will stop reading data from the CR10X until
the next scan interval. As data is transmitted, memory will get freed up for the next interval.
The CR10X,MAXQ,N setting is used to limit the number of group reports created with each
scan. For example, if MAXQ is set to 20, each scan will read, at most, 20 group reports. 20 more
will be read at the next interval, etc. There is no provision for limiting the length of the transmit
queue as in the MRC-550 data acquisition unit. In effect, limiting the transmit queue length can
be accomplished by setting the SNP,TTL,NN time to purge reports older than the given number
of minutes.
5.7.11 Data Scaling
Two data formats are supported, and must agree with the setup of the internal CR10x Program.
Only the low-precision format is currently supported.
The CR10X,SCALE,CR10X format will use the Campbell Scientific floating point format and
assumes the sensors are calibrated in engineering units within the CR10X.
The CR10X,SCALE,INT format assumes each sensor is calibrated in integer mV, and formats
the data in 2's complement integer Hexadecimal format by truncating the fractional part of the
floating point number. Example: CR10X outputs 103.7, MRC-565 truncates it to 103, then
converts it to hex 0067. The value -103.7 will be converted to hex FF99. The cr10X maximum
low-precision values are 13 bits where +6999 is converted to hex 1B57 and -6999 is converted to
hex E4A9. The MRC-565 uses 16 bits for each sensor data value, but the MRC-550B/C (and
some customers) is limited to 12 bits of significance.
5.7.12 Modem Enable
By default, the use of the MODEM ENABLE line is turned OFF and the RING line is tied high
to keep the CR10X awake. For applications that require very low power, the CR10X can go to
sleep between operations, and must be woken up to communicate with it. This mode is enabled
in the MRC-565 by the command: CR10X,MODEM ENABLE,ON. When the MRC-565 wants
to communicate with the CR10X, it raises the RING line, and waits for the CR10X to raise the
ME line. The ME line must be tied to the RTS line of the MRC-565. Once the ME line is high,
the MRC-565 lowers the RING line and begins its command sequences. When the last
command is completed, the MRC-565 sends an "E<cr>" command to the CR10X to put it back
to sleep.