Specifications

Section 12. Serial Input and Output Functions
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if the datalogger is allowed to go into its low power sleep mode between
infrequent ModBus queries.
Some ModBus devices (e.g., some RTUs made by Bailey Controls that use less
common CPUs) require reverse word order (MSW/LSW) in the floating point
format. The datalogger currently does not support this less common word
order. (There are experimental versions of some datalogger operating systems
that have used the reverse word order.) Some software packages have a set
setting to work with this original ModBus format. For example, the “Modicon
32-bit floating point order (0123 vs. 3210)” advanced option must be enabled
for the ModBus object in National Instruments’ Lookout.
ModemHangup (ComPort) … EndModemHangup
The ModemHangup and EndModemHangup instructions are used to enclose
code that should be run when a COM port hangs up communication.
Syntax
ModemHangup ( ComPort )
instructions to be run upon hangup
EndModemHangup
Remarks
The ModemHangup instruction indicates the beginning of the code; the
EndModemHangup indicates the ending. The code is entered in the
declarations section of the program, prior to the main program (defined by the
BeginProg/EndProg instructions). When the datalogger detects that a COM
port is hanging up, the ModemHangup code will be run.
This instruction set is most often used with modems that must be sent a
command sequence to disconnect and go into a low power state.
Note that each COM port operates independently; therefore, commands to hang
up modems can be processed concurrently.
ComPort The ComPort parameter specifies the communication port and mode
for this instruction.
This instruction runs sequentially from the processing task sequencer,
regardless of whether the datalogger is in pipeline or sequential mode.
SerialClose (ComPort)
The SerialClose instruction is used to close a communications port that was
previously opened by the SerialOpen instruction.
Syntax
SerialClose (ComPort)
Remarks
If this instruction is set equal to a variable, the result will be True (-1) of the
port was opened or False (0) if it was already closed.