HIKVISION DS-2TE127-G4A Reference Blackbody - a look inside .... by Fraser

[Fraser]

This is a very quick post to show those who may be interested in what is inside the casing of a HIKVISION DS-2TE127-G4A Reference Blackbody.

The DS-2TE127-G4A was created to assist with Fever Screening that used thermal imaging cameras. The Reference Blackbody produces an accurate thermal signature in the cameras field of view that is used by analysis software to improve the cameras thermal measurement accuracy.
The Reference Blackbody must be accurate and stable in order to meet the specified medical role. As such these units can be very well made using known quality components and were very expensive. The HIKVISION unit is such a  design and is well designed using quality parts. 

The specification for the HIKVISION Reference Blackbody is as follows:

Temperature range: Ambient +5 Celsius to +50 Celsius
Temperature Resolution: 0.1 Celsius
Temperature Accuracy: +/- 0.1 Celsius
Temperature Stability: +/- 0.1 Celsius
Effective Emissivity: 0.97 +/- 0.02
Aperture diameter: 70mm
Power Supply: 100Vac to 240Vac
Power Consumption : 20W

As can be seen, the specification is more than adequate to test the measurement accuracy of a thermal imaging camera or IR thermometer 

Inside the units casing there is a well designed layout of components comprising the following main elements:

1. MeanWell LRS-50-24 24V 2.2A Switch mode Power Supply
2. OMRON E5CC high quality PID temperature controller
3. OMRON G3NA-D210B Solid State Relay
4. Custom heater assembly incorporating a coated Aluminium emission plate and KAPTON insulated foil element heater.

The unit is cooled with a small fan.

The temperature to which the PID temperature controller may be set is limited in its settings. These limits may be changed if desired and the design of the heater assembly appears good for at least 100 Celsius if required. I recommend a maximum temperature of 80 Celsius however. The temperature range "as supplied" of Ambient +5C to +50C is still enough for a normal "2-Point" calibration 

To the pictures:

[Fraser]

Disassembly begins......

[Fraser]

Continued....

[Fraser]

Heater and Emission plate Module.

Note:

a) The PT100 RTD temperature sensor conductors are inside the white PTFE insulated cable
b) The black wires connect to the 24V foil heater
c) The hole in the top of the module is for the use of a PT100 calibration thermometer to calibrate and check the accuracy of the BlackBody.
d) The heater is a Kapton film coated foil type sandwiched between the back-plate and emission plate
e) The thermal insulator between the emission plate and the BlackBody front panel appears to be nylon

[Fraser]

Well there you have it.... the interior of the HIKVISION DS-2TE127-G4A.

I like what I see inside the unit and it is accurate but that does not surprise me as the OMRON PID controller is a pretty expensive unit to include in the BoM for the manufacturer. They could have used a far less expensive PID temperature controller costing <10% of the OMRON unit.... but that component is critical to the final accuracy and stability of the BlackBody so the OEM elected to use the quality product.

Fraser

[Fraser]

Also of interest in this particular BlackBody is the OEM's use of a COTS Solid State Relay. In the DAHUA equivalent BlackBody, they designed their own "SSR" PCB rather than using a COTS component. This was presumably to save on the BoM cost. Once again, the HIKVISION unit uses a quality branded product for the SSR rather than a cheaper "no name" component that we commonly see in inexpensive equipment.

Finally we can see that the HIKVISION unit incorporates a decent branded switch mode power supply in the form of the MeanWell LRS-50-24. MeanWell power supplies are a brand that I like to see in equipment as they are generally considered to be of decent design and build.

I see no evidence of cost cutting in the HIKVISION DS-2TE127-G4A and its high cost may well be due to HIKVISION wishing to respond quickly to a market need and used good quality COTS components rather than trying to build their own modules or source cheaper alternatives.

These compact and accurate reference Blackbody units are a direct result of the Global CoronaVirus Pandemic emergency management response and they are now appearing on eBay at far more affordable prices   This unit cost £90 delivered and is in great condition with no damage to the emission plate coating and almost no dust inside. I suspect that it was a Demo unit due to its lack of dust inside and on the fan blades.

Fraser

[Fraser]

The inside of a nicely made DAHUA Reference Blackbody may be seen here......

https://www.eevblog.com/forum/thermal-imaging/danua-reference-blackbody-under-the-covers-)/msg4139053/#msg4139053

To see what a "Cost Cut" Blackbody looks like take a look at my investigation of the BX-350. That BlackBody was poorly designed, used poor components and was, quite frankly, Junk ! I am rebuilding my unit to a better standard to make it of some use to me in my thermal camera repair work.

https://www.eevblog.com/forum/thermal-imaging/bx-350-portable-blackbody-temperature-reference-teardown-by-fraser/msg4393027/#msg4393027

Fraser

[Fraser]

HIKVISION DS-2TE127-G4A BlackBody data sheet and manual....