Chapter 4 _________________________________________________________________ OperationVAISALA ________________________________________________________________________ 29CHAPTER 4OPERATIONThis chapter contains information that is needed to operate the HMP60and HMP110 series probes.Getting StartedNOTE Before you connect an HMP60 or HMP110 series probe to a device, it isrecommended to power off the device.When the probe is connected to a power supply, there is a delay as theprobe starts up and the analog output stabilizes. The delay depends on theoutput type, and on the operating voltage that is supplied to the probe:- Probes with analog output:- 4 s at operating voltage 13.5 ... 16.5 VDC- 2 s at other valid operating voltages- Probes with digital output: 1 sSerial Line CommunicationNOTE In analog probes, serial line communication is intended for service useonly.HMP60 and HMP110 series probes support two-wire RS-485communication. The RS-485 interface is non-isolated and offers amaximum communications rate of 57600 bits/s.There is no internal termination for the RS-485 on the probe. Use oftermination resistors is not recommended. If the resistors are used, thepossible increase in current consumption should be taken into account.
