Vaisala HUMICAP HMP155, User Manual, Page: 3 / 102

Table of contents
1. About this document .....................................................................................7
1.1 Version information .......................................................................................... 7
1.2 Related manuals ................................................................................................7
1.3 Documentation conventions ............................................................................7
1.4 Trademarks ........................................................................................................ 8
1.5 Patent notice ..................................................................................................... 8
2. Product overview ............................................................................................ 9
2.1 Vaisala HUMICAP Humidity and Temperature Probe HMP155 .................... 9
2.1.1 HMP155 models ..........................................................................................9
2.1.2 Humidity sensor options .........................................................................10
2.1.3 Features and options ................................................................................ 11
2.2 HMP155 parts ....................................................................................................13
2.3 Heating options ............................................................................................... 13
2.3.1 Warmed probe option .............................................................................14
2.3.2 Chemical purge option ............................................................................14
2.3.3 Extra sensor heating (Xheat) option ..................................................... 16
2.4 Additional temperature probe option ...........................................................17
2.5 Connection cover option ................................................................................ 18
2.6 Safety ................................................................................................................ 18
2.6.1 ESD protection ......................................................................................... 19
2.7 Regulatory compliances ................................................................................. 19
3. Installation .......................................................................................................20
3.1 Mounting in radiation shields ........................................................................20
3.1.1 Mounting HMP155 and DTR13 on horizontal sensor support arm .....20
3.1.2 Mounting HMP155 inside radiation shield DTR503A ...........................24
3.1.3 Installation in Stevenson screen ............................................................30
3.2 Installing HMP155 .............................................................................................31
3.3 Wiring HMP155 ................................................................................................32
3.3.1 8-pin connector ....................................................................................... 32
3.3.2 Temporary RS-485 connection option ................................................. 35
4. Operation .........................................................................................................36
4.1 RS-485 interface .............................................................................................36
4.2 Serial line communication ............................................................................. 36
4.2.1 Installing driver for USB cable ............................................................... 37
4.2.2 Connecting HMP155 with PuTTY terminal software ............................37
4.3 HMP155 commands ....................................................................................... 39
4.4 Measurement commands .............................................................................. 42
4.4.1 R command ..............................................................................................42
4.4.2 S command .............................................................................................. 42
4.4.3 INTV command ........................................................................................42
4.4.4 SEND command ...................................................................................... 43
4.4.5 SMODE command ...................................................................................43
4.4.6 OPEN command ......................................................................................44
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