HMP155 USB Interface Commands

You can use a special USB cable from Vaisala to check on the performance of an HMP155. To communicate, first install the driver. This is easier said than done but 'vaisala instrument finder' in google may get you close, then download directly from Vaisala. I can only find it via google, not through searching the Vaisala online software downloads. Also handy is the user manual:

• http://www.vaisala.com/Vaisala%20Documents/User%20Guides%20and%20Quick%20Ref%20Guides/HMP155_User_Guide_in_English.pdf

Check in the Device manager to see which COM port the cable installed as. For me it is listed as COM3. You can also see if you start CSI's Device Config. It shows up there as 'Vaisala USB Device COM3'.... however, the commsettings are not compatible with Device Config so you'll need to try Putty. The settings should be:

• 4800 Baud
• Even Parity
• 7 Data Bits
• 1 Stop Bit
• No hardware flow control

Plug everything in and here a few commands to try:

vers -- Version of probe
smode run -- start automated output of current sensed values
smode stop -- stop automated output
seri -- set the baud etc
? -- I got a read out of last calibration date, serial number and such.

Check the manual for much more. All of chapter 4 covers things you can do from this interface.

Super Site Specific

Default from the factory will be the above: 4800 / E / 7 1

Baud P D S     :     4800 E 7 1

To work with the MD-485 type the following.

seri 9600 n 8 1

This will be the response:

Baud P D S     :    9600 N 8 1

Next, change the format of the default message:

FORM 5.3 T " " RH \n

The Default is:

RH= 27.6 %RH T= 26.7 'C

Changing the format results in this:

   17.164    49.757

Lost to history but I'm sure there is a reason, the MD485 has baud rate 19200 for talking RS232 with CR1000 but 9600 baud talking to HMP155.