itsensor RGA801F Sunmeter Pro User Manual
- June 6, 2024
- itsensor
Table of Contents
itsensor RGA801F Sunmeter Pro User Manual
GENERAL DESCRIPTION
The SunMeter PRO (SM PRO) is a high technology electronic device primary
designed to accurately measure the solar radiation and make it available to
the user in the best suitable way for its applications.
It’s mainly intended, but not limited, to be used in solar energy conversion
applications (both thermal and photovoltaic) for preliminary studies, for
commissioning testing and for continuous performance checking and monitoring.
It’s based on a sensing silicon element that through our proprietary TZOS
(True Zero Ohm Shunt) technology is sampled and managed by a high performance
DSP (Digital Signal Processor) in order to enhance the signal precision and
stability, achieving results that are comparable to best class radiometers.
Its monocrystalline silicon cell is laminated with small micro prismatic glass
for photovoltaic modules and E.V.A., this improves its durability and
stability of measurements over time.
It’s equipped with an additional input for an external PT100 RTD element in
order to sense the temperature of nearby items, i.e. photovoltaic modules,
ambient, etc.
The measures can be read by two outputs: a “universal” multistandard analog
output for all old-fashion viewing devices and dataloggers and a powerful,
versatile EIA/TIA-RS485 bus interface with the well known industry standard
protocol Modbus RTU.
FEATURES
PART LIST
– SM PRO with aluminium bracket
– female M12 8 pin circular connector
– 1 long stainless steel screw (temporary positioning)
– 2 short stainless steel screws (permanent positioning)
– instruction manual
FINAL TEST AND CALIBRATION
REPORT: S/N ………………………………………………………..
OPER…………………………………………………….
DATE……………………………………………………..
Important: the case presents a hole with a diameter of a few mm, this hole is terminated by a transpiring membrane whose purpose is the barometric compensation to avoid condensation. DON’T PERFORATE. WARRANTY VOID IF REMOVED OR PERFORATED.
ASSEMBLY
SM PRO is provided with a bracket to apply it to structures or directly to a PV module as shown in Fig. 1 and 2:
We suggest to mount SM PRO on the bottom side of a PV module because, if applied on the top side, it may be chosen by a bird as a springboard! The same considerations apply when fastening to a structure’s profile. Stainless screws are provided for permanent mounting of SM PRO on your PV plant.
CONNECTIONS
The IP67 8-pin circular male connector carries all the signals to and from the SM PRO as in Tab. 1 and Fig. 3, which shows a back view of the female connector (the fourth column indicates the colours of cables in the free pin version):
- Only for the complete model (Digital and Analog Output) We strongly suggest to use a shielded connection cable with twisted pairs, AWG22 / 0.32mm2
Notes:
-
if analog output is used, please pay attention to choose a power supply greater than the compliance voltage, see also note 3.
-
balanced differential bus RS485 needs to be terminated, at the extremities of the bus, by a 100-120 resistor (1/4 W) between RS485+/RS485- lines in order to avoid signal’s reflections. In the case that SM is the device at one extremity, place the resistor into the supplied female connector. Even if RS485 have 7/+12Vdc common mode rejection range, normally sufficient to compensate ground potential difference between connected devices, it is strongly recommended to always carrying a ground reference among the bus’s signals and to connect it to the SM PRO’s Signal GND.
-
please check load restrictions:
• in voltage modes (0÷5 / 0÷10 V) minimum load impedance is 250 / 500 , we recommend a load impedance > 5 k
• in current modes (0÷20 / 4÷20 mA) maximum load impedance is 1.2 k, we recommend a load impedance in the 200-500 range
• the compliance voltage (maximum output voltage) at full 20 mA output current and beyond, is about 2.5V less than power supply voltage so choose it accordingly in order to leave sufficient margin. -
the digital input need to be activated by shorting to GROUND (either supply or signal, latter preferably). Do not attempt to supply voltage to this input.
MODBUS PROTOCOL
Modbus is a Master-Slave protocol that is widely used as an industry standard. It is simple, efficient and reliable. It can be easily used to access and collect data or exchange information between digital systems over a serial line local bus (and with its TCP/IP extension through a LAN or World Wide Web). Please refer to specific detailed documentation and implementations freely available at www.modbus.org
SM PRO is a Modbus RTU slave that implements the following standard access functions:
Please note that in the current implementation of SM PRO function codes 0x03 and 0x04 are equivalent and address the same data area.
Data is accessible through Modbus’s functions by 16 bits units called “registers”. In the current implementation of SM PRO these registers are available:
Please note that, conventionally, Modbus register’s numbering starts from 1 but register’s addressing start from 0 so, to obtain the register’s address you had simply to subtract 1 from its number. That’s meaningful depending on, as a master, you are using a high level Modbus utility/program (that normally refers to the registers’ number) or a low level driver (that normally directly works with addresses).
CALIBRATION
Each SM PRO is factory calibrated, with 2 reference points by a primary sensor referred to a first class radiometer. Re-calibration is recommended every 2 years in order to maintain the original precision.
The analog output is normalized to a full scale range of 0 ÷ 1500 W/m2 for irradiance and -30 +90 °C for temperature. Values outside these ranges are saturated (to min or max output’s value). Analog output reading ratios Tab. 4:
OPTIONALS
Available upon request:
– Analog output adapter kit for dataloggers with 0-40 mV or 0-100 mV input
range – EzTemp: PT100 RTD element for PV modules temperature sensing, 2 wire,
with fast mounting bracket for PV mounting profiles and auto-fitting system
– SMscan: handheld LCD display unit and SM power supply for direct real-time
reading of irradiance and temperature, available in cabled and wireless
versions
CONTACTS For further information, contact us:
[email protected]
+39 0425 1810834
ITSENSOR Srl- Viale Porta Adige 45 – Torre Uffici Censer – 45100 Rovigo (RO) – ITALY www.itsensor.it +39 0425 1810834 [email protected]
References
- 📧[email protected]
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- ITSensor - Industrial Technology Webstore - ITSensor
- ITSensor - Industrial Technology Webstore - ITSensor