AMPBOX Amplifier

AMPBOX Amplifier

AMPBOX is a current loop amplifier for the complete range of solar radiometers.
Most radiometers have no power supply, the measured radiation is used to create an output signal in the mV range and amplification is often required, especially when signal cables of more than 50 m are used between the radiometer and data collection equipment.

The input and output of the AMPBOX are galvanically isolated to minimize feedback and to protect the data collection equipment. When installation is in EMC-unfriendly environments, amplification can prevent interference problems.
The 4 to20 mA interface makes it easy to connect to most data collection equipment. An output of 2 to 10 Volt can be created with the use of a 500 Ω resistor and a suitable power supply.

As standard amplification is set to 2 mV input equals 1 mA output. On request the amplification can be adjusted to suit the sensitivity of a specific radiometer, for example with a pyranometer this results in 4 to 20 mA equals 0 to 1600 W/m².

AMPBOX is IP66 approved and suitable, like all Kipp & Zonen radiometers, for outdoor installation under all weather conditions. Two cable glands and large internal screw terminals allow for easy connection of radiometer and output wires. Radiometer temperature sensors can be connected and passed through AMPBOX (without amplification).

Specifications

Downloads

Instruction sheets

• Instruction Sheet - AMPBOX Signal Amplifier

Brochures

• Brochure - AMPBOX Signal Amplifier
• Interface options for Kipp & Zonen Pyranometers

Declarations

• Declaration of Conformity AMPBOX Amplifier

Manuals

• Manual - AMPBOX Signal Amplifier

FAQ

• Can I convert the current output (mA) of an AMPBOX to Volt?

  • Yes you can, by using a shunt resistor and a suitable power supply unit (PSU). You will need a shunt resistor of 500 Ω to convert the output current (4..20mA) to a voltage output of 2-10V.  Or you will need a shunt resistor of 50 Ω to convert the current to a voltage output of 0.2-1V.

    

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• The AMPBOX has a range of range 0 - 1600 W/m2 for 4-20mA. The CMP 3 pyranometer has a sensitivity of 16,51 μV/W/m². And the PQS 1 PAR quantum sensor has a sensitivity of 5,59 μV/μmol/m²s. How can we calculate the output signal?

  • The AMPBOX is set for 0 - 1600 W/m²  for 4 – 20 mA
    For CMP 3 with 16.51 μV sensitivity, this is 0 - 16.51 * 1600 μV =0 - 26.416 mV for 4 - 20mA  (delta = 16 mA)
    Sensitivity AMPBOX = 26.416 mV per 16 mA  =  1.651 mV per 1 mA or 1651 μV per 1 mA

    Now connected PAR with 5.59 μV/μmol.     1651 / 5.59 = 295.35 μmol per mA

    Therefore:
    0 μmol = 4 mA 
    295.35 μmol = 5 mA etc.
    4725.6 μmol = 20mA as maximum input

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• Can we measure low level photosynthesis radiation (0,1 μmol/m²s) with the PQS 1 and the AMPBOX?

  • No, 0,1 μmol/m²s input will result in a very small change on the output of the AMPBOX (around 4,00033 mA). This is outside the accuracy of the AMPBOX and the accuracy of the PAR Lite.

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• Can I use a METEON data logger in combination with the AMPBOX?

  • No, the METEON will not work together with an AMPBOX.

    With a 10 Ohm resistor the 20 mA output from the AMPBOX can be converted to 0.2 V max signal (max for the METEON). But the METEON cannot deal with the zero offset from the AMPBOX (4 mA).

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• Each AMPBOX corresponds to a specific pyranometer, could you please specify this?

  • If the AMPBOX is purchased together with a new pyranometer, or for use with an existing pyranometer, it has the sensitivity of that pyranometer programmed internally.  In this case 0-1600 W/m2 of irradiance on the pyranometer produces 4-20mA from the AMPBOX. The serial number of the pyranometer matching the AMPBOX should be present on a label on the AMPBOX.

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• What is the accuracy calculation from a radiometer to the input of the AMPBOX? And the accuracy calculation out of the AMPBOX?

  • The AMPBOX can be delivered in two versions:

    • standard, then the gain is 1 mV = 1 mA
    • adjusted, then the gain is set to 0 – 1600 W/m² = 4 – 20 mA

    The AMPBOX has a 20 bits A/D on the input and a 16 bits A/D on the output.

    The maximum error from the AMPBOX is ±0.05% of span or ±10 µV (over the full temp range)

    This means in daily use that the additional error of the AMPBOX is far below 1 W/m² for all radiometers.

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• What does “gain range” mean in the AMPBOX specification? And how is this value useful?

  • The gain range is the ability to adjust the amplification to the sensitivity of the radiometer:
    

    • Gain adjust --> 0.1 to 4 mA/mV
    • Input voltage range --> -12 to 50 mV

    As mentioned above the amplification can be adjusted to 0- 1600 W/m² = 4 – 20 mA.
    In this case 100 W/m² change on the input gives 1 mA change on the output.
    The benefit is that two different sensors with different sensitivities have an identical output from the AMPBOX.

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• In the AMPBOX specification what does “Zero adjust” mean? And how is this value useful?

  • The zero adjust is used for the pyrgeometer to allow negative inputs.
    The pyrgeometers are adjusted for -300 to +100 W/m² = 4 to 20 mA.
    So 100 W/m² change on the input gives 4 mA change on the output. The zero point for the pyrgeometer is set to 16 mA. This is because a pyrgeometer can be more negative than positive.

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Accessories

Relevant news items

11/29/2011 New standard gain setting applied inside the AMPBOX

5/10/2011 Programming the AMPBOX signal amplifier

Application examples

7/31/2015 Testing Solar Ovens to Disinfect Water in Cameroon