Specifications

OPERATIONS
Page 101 MRC-565 Packet Data Radio Operations & Maintenance
Sensors should respond to a command in 15ms, but they can take up to 100ms to wake up from a
sleep state and respond to the first command after the BREAK. The master (in this case the
MRC-565 Radio) will retry commands if it gets no response. The first timeout is 100ms and
subsequent retries will time out after 20ms. The MRC-565 basic timing internal clock is 10ms
per “tick” so all of the timing is rounded up to the next 10ms tick.
5.10 Generic Data Logger
The MRC-565 includes a set of device drivers for its serial ports. These have been customized
for various external devices over the years as the requirements became known. The SDATA
command was created to allow a simple text-based interface to send data groups to the MRC-565
for transmission to the master. Any customer that could configure their data report to meet this
format could interface his data logger with no change in the MRC-565 software. From 1 to 16
groups can be input, and there can be from 1 to 16 sensors per group. Each sensor data value is
formatted into a 16-bit binary value for transmission, then converted to engineering units by the
Data Center or Host software.
Some date loggers have a complex and non-configurable interface protocol, and cannot meet any
of the currently implemented protocols, but they can output data reports on a serial port as if it
were connected to a line printer. The GENERIC data logger driver has been created for this type
of interface. Some things can be setup by user commands to configure the report parsing, within
a limited set of constraints, and allow the MRC-565 to create SDATA type messages from the
ASCII text reports.
The following sections describe what can be done to adapt the MRC-565 to a variety of report
formats.
5.10.1 Typical Report Formats
A typical report printed by a data logger has one line, or a set of lines for each report. There are
usually two types, single-line reports, and multiple-line reports. An example of each type would
be as shown below:
Single line report examples:
123.4 19.8 33 99 -1089.45 ….<cr><lf>
or
10/14/02 09:15:00 +123.4 +19.8 +33 +99 -1089.45 ….<cr><lf>
Note that the report ends with carriage return and linefeed characters, and may or may not print a
date and/or time. The data fields are usually separated by blanks, and the data values may or
may not contain a sign or decimal point. The line is usually output by the data logger as the
report is placed into the devices' memory in real-time. There is no provision for error checking,
but if the serial port cable is wired correctly with shielding, etc., it may be reliable enough.