Kipp & Zonen SMP series Instruction Manual

Also see for SMP series: Quick start guide

Kipp & Zonen SMP series Instruction Manual Manual pdf 20 page image

Connection to a RS-485 NetworkThe digital interface can be connected to a 2-wire RS-485 network as shown below.The slaves and master may be a SMP pyranometer or other devices. If a SMP pyranometer is the last device on the network aline terminator (LT), consisting of a 120 Ω or 150 Ω resistor, must be connected between terminals A/A'/- and B/B'/+. Neverplace this line termination on the derivation cable. It is also required to install the pull up and pull down resistors as shown.The value of these resistors must be between 650 Ω and 850 Ω.2.9.3 Analogue voltage outputThe SMP-V (voltage output versions) have been factory set such that an output of 0 Volts represents -200 W/m² (this will neverbe reached in practice), and the full-scale output of 1 Volt represents 2000 W/m².The voltage output range in W/m² can be changed by the user with the supplied PC software. The maximum recommendedirradiance for the SMP3 and SMP6 is 2000 W/m² and for all other SMP’s it is 4000 W/m².The measurement range must start from a negative value in order to show (small) negative readings, for example night-timeoffsets, because the analogue output itself cannot go negative. For the default setting of 0 to 1 Volt representing -200 to 2000W/m² the range is actually 2200 W/m² with a zero offset of 200 W/m².The irradiance value ( E solar) for the default setting can be simply calculated as shown below.E solar = Solar radiation [W/m²]V = Output of radiometer [Volt]If the pyranometer is used in atmospheric conditions it is advised to keep the range as factory set.Slave 1 Slave nMasterCommonBalanced pairLT LTPull downPull up5 V20