The L-420 radiometer-photometer is designed to build optical radiation measurement systems of any use (e.g. data acquisition, control of technological processes, etc.). It is a hardware platform intended to measure illuminance, irradiance and luminance (light, energy or photon).

Class APC



Specification of the instrument is based on the Customer’s demands. It comprises the type of the measured quantity, spectral sensitivity, number and values of measurement ranges. The full name of the instrument is created on the basis of its specification on the Customer’s demand. The instrument can co-operate with the 4-20mA current loop or RS232 digital interface with the use of SONBUS or MODBUS RTU protocol.


The L-420 meter automatically compensates the influence of temperature on the measurement result. The User can change time of averaging of results in the range of 160ms – 10.24s.


Technical data

Supply voltage:
+9 to +30 V
Supply current (current loop is on):
3.5 - 22 mA
Supply current (current loop is off):
4 mA
The amount of ADC conversions to averaging the result:
1 to 64
ADC conversion time:
160 ms (± 50 ppm)
Measurement resolution:
17 bits
Current loop resolution:
16 bits
The maximum number of measurement ranges:
Degree of protection:
IP65 (IP68 on demand)
Ø 44 × 80 mm