Vaisala HMT120 - Manual (Page 25)

Chapter 4 _______________________________________________________________ Service Port
VAISALA ________________________________________________________________________ 23
CHAPTER 4
SERVICE PORT
This chapter describes the service port of the HMT120.
Using the Service Port
HMT120 motherboard has an 8-pin RJ-45 connector for service use.
Service port uses RS-232 signaling levels. Vaisala offers an optional
USB cable (Vaisala order code 219685) for connecting the transmitter to
your PC.
NOTE The service port is intended for short-term use such as calibration. For
permanent installation, use the analog output.
Connecting a PC to the service port may cause erroneous analog output
because of a possible ground loop. Use the service port for service only
and disconnect the PC after the service operation.
The cable can also provide operation power to the transmitter, so the
wires at the screw terminals need not to be connected in order to operate
the transmitter.
If you have not used the HMT120 USB cable before, install the driver
that came with the cable. Refer to section Installing the Driver for the
USB Cable below for detailed instructions.
Installing the Driver for the USB Cable
Before taking the USB service cable into use, you must install the
provided USB driver on your PC.
1. Check that the USB service cable is not connected. Disconnect the
cable if you have already connected it.
2. Insert the media that came with the cable, or download the latest
driver from www.vaisala.com .
3. Execute the USB driver installation program (setup.exe), and
accept the installation defaults. The installation of the driver may
take several minutes.