Vaisala HMT140 User Manual

Also see for HUMICAP HMT140: Quick guide Quick guide User guide Quick guide

Contents

Vaisala HMT140 User Manual Manual pdf 38 page image

HMT140 Function Modes34 VAISALAWhen new activity occurs, the HMT140 will wake again,connect, then go back to sleep after five seconds.Transmitter ModeWhen the HMT140 is powered on and the HMT140Configuration Cable is not plugged into it, data is transmittedaccording to the transmit settings.In Transmitter mode, the HMT140 spends most of its time ina very low power state (sleep). When a transmit period is due,it powers up the radio, attempts to link to the specifiedwireless network, transmits its data and then goes back tosleep. The HMT140 transmits based on the configuredtransmit period or when it is entering an alarm state.Transmission of DataThe HMT140 will go through the following steps in order toconnect to a network and deliver data:1 Associates with the network.2 HMT140 authenticated by the network (depends on thetype of security).3 Requests IP from DHCP Server (if set to dynamic IP)4 HMT140 receives request from Name Server IP addressof hostname (if a hostname is used for the Destinationaddress and DNS Server specified).5 Sends data.6 viewLinc returns acknowledgement.Transmit AttemptsThe HMT140 will initiate a Transmit Attempt repeatedly(typically every 30 seconds) until either an acknowledgementis received from the host, or the number of tries has beenexhausted. It follows this transmission mechanism bothwhen the transmit period arrives and for alarm attempts.