Campbell CR3000 Micrologger, Operator'S Manual, Page: 326 / 644

Section 7. Installation
326
packet. For this reason SerialOpen() leaves the interface powered up so no
incoming bytes are lost.
When the CR3000 has data to send with the RS-232 port, if the data are not a
response to a received packet, such as sending a beacon, it will power up the
interface, send the data, and return to the "dormant" state with no 40 second
timeout.
Q: How can I reference specific characters in a string?
A: The third 'dimension' of a string variable provides access to that part of the
string after the position specified. For example, if
TempData = "STOP"
then,
TempData(1,1,2) = "TOP"
TempData(1,1,3) = "OP"
TempData(1,1,1) = "STOP"
To handle single-character manipulations, declare a string with a size of 1. This
single-character string is then used to search for specific characters. In the
following example, the first character of string LargerString is determined and
used to control program logic:
Public TempData As String * 1
TempData = LargerString
If TempData = "S" Then ...
A single character can be retrieved from any position in a string. The following
example retrieves the fifth character of a string:
Public TempData As String * 1
TempData = LargerString(1,1,5)
Q: How can I get SerialIn(), SerialInBlock(), and SerialInRecord() to read
extended characters?
A: Open the port in binary mode (mode 3) instead of PakBus-enabled mode
(mode 0).
Q: Tests with an oscilloscope showed the sensor was responding quickly, but the
data were getting held up in the internals of the CR3000 somewhere for 30 ms or
so. Characters at the start of a response from a sensor, which come out in 5 ms,
were apparently not accessible by the program for 30 ms or so; in fact, no data
were in the serial buffer for 30 ms or so.
A: As a result of internal buffering in the CR3000 and / or external interfaces, data
may not appear in the serial port buffer for a period ranging up to 50 ms
(depending on the serial port being used). This should be kept in mind when
setting timeouts for the SerialIn() and SerialOut() instructions, or user-defined
timeouts in constructs using the SerialInChk() instruction.