Vaisala HMP110REF

User's Guide _______________________________________________________________________
36 ___________________________________________________________________ M211060EN-H
Accessing Serial Line Command
Interface (RS-485 Mode) from Analog or
Modbus Mode
Follow the steps below to connect to the serial line when the probe is in
analog or Modbus mode, or if you have entered incorrect communication
settings, for example, with Modbus configuration registers and the
settings need to be restored using the serial interface. You must use the
Vaisala USB cable (Vaisala order code: 219690) in this case.
1. Connect the USB cable to the PC and install the driver, if
necessary. Do not connect the cable to the probe yet.
2. Open the terminal program and open a connection to the
corresponding COM port using the default settings 19200, 8, N, 1,
no flow control.
3. Select the Serial settings category, and check that the correct COM
port is selected in the Serial line to connect to field.
You can check which port the USB cable is using with the Vaisala
USB Instrument Finder program that has been installed in the
Windows Start menu.
4. Click the Open button to open the connection window and start
using the serial line.
5. Keep the Enter key pressed down and connect the other end of the
USB cable to the probe. This will cause the probe to start in RS-
485 mode, using the default serial settings. You can now use the
probe with the terminal program (for information on available
serial commands, see List of Serial Commands on page 39).
6. To prevent the analog or Modbus mode from being restored on the
next power-up, select a different serial mode with the smode
command (see Set Serial Interface Mode on page 44).
7. To switch back to analog mode or Modbus mode from the serial
mode, use the smode analog command or the smode modbus
command to select analog or Modbus mode. Reset or power cycle
the probe to restart in the selected mode.
NOTE
The probe cannot be used with the MI70 hand
-held indicator when the
probe is in analog mode. To use the probe with MI70, enable the serial
mode as instructed above.