FLIR PM570 Professional thermal camera teardown and design commentary by Fraser

[Fraser]

Introduction

Dear readers, I have decided to create a thread on one of my favourite thermal imaging cameras, namely the FLIR PM570 professional preventative maintenance thermal camera of 1997. For me, this camera model represents the transition from cooled thermal imaging to uncooled microbolometer based thermal imaging in the Professional thermal imaging sector. The PM570 has a similar outward appearance to the AGEMA/FLIR Thermovision 550 Stirling Mechanical cryo-cooler equipped MWIR camera, but it is the first hand portable uncooled microbolometer LWIR thermal camera that FLIR released. I was one of the first people in the UK to test this camera with a view to it replacing the THV 550 cameras in our inventory. I loved the solid, well engineered, design and grew to accept the limitations of the first generation uncooled microbolometer within it. I went on to collect the various FLIR PM series thermal imaging cameras and I have several in my collection. The PM570 was succeeded by the following cameras .....

PM515
PM520
PM525
PM545
PM575
PM595
PM675
PM695

As we shall see in this thread, all of these PM series cameras contain an electronics package that can be traced back to the original PM570, and even some of it back to the THV550 cooled camera ! AGEMA camer up with a great camera design and FLIR ran with it for many years before it was retired when the PM695 was retired from sale. It could be argued that the replacement Pxx series was not such a nice design (an Ugly Duckling?) but I will leave that discussion for another time 

In this thread I intend to include a teardown of the PM570 camera, a commentary on its design and information that may be of use to fellow PM series camera owners. I intend for this thread to become a PM series camera technical reference source. In the past have have been hesitant about posting too much information on this capable thermal imaging system as there was/is some sensitivity surrounding the complete reverse engineering that I carried out on it circa 2015. Sadly I will not be posting the full schematics of the camera but I can provide a high level understanding of the cameras electronic design to aid those wishing to diagnose faults on these units or just better understand the technology within these professional cameras of the late 1990's and early 2000's. This thread will be an ongoing "project" for me that i will populate as and when time permits. I will include teardowns and information on the later PM series cameras here as well so that the differences may be seen and understood.

Well that is the introduction. I will begin uploading the PM570 thread content soon 

Enjoy !

Fraser

[Fraser]

First, the complete FLIR PM Series family with a guest appearance from the daddy of them all, the AGEMA THV550 cooled MWIR camera 

[Fraser]

The PM series that came after the PM570 (despite some having a lower model number!)......

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[Fraser]

The end of the series, the PM675 and PM695 cameras......

The PM695 came with a monochrome or colour visible light camera depending upon the buyers preference.

These cameras also incorporated auto-focus functionality.

[Fraser]

To the teardowns. I have photographs from two PM570 teardowns and I will upload both here in case different features are visible.
The first teardown pictures are from my very first PM570 purchase that came to me 'as new' but would not complete boot. The second teardown is a PM570 that had served its owners well, but not without cost.... its case showed evidence of hard use and a significant crush event. More detail in the commentary before those pictures. I will follow the teardown images with a commentary on the cameras design.

Teardown 1 ........

[Fraser]

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[Fraser]

Teardown 2

This particular PM570 had all the evidence of a hard life on its casing. It was bought in used, working but with a non-functional Electronic View Finder. Upon examining the camera it was noted that it had suffered mechanical trauma from what appears to be a crush event, rather than a drop. The following damage was found on the camera during its inspection.....

1. The EVF has been forced down hard onto the top surface of the cameras casing causing an indentation.
2. The rear of the casing above the battery and PCMCIA bays has suffered cracking of the vertical divider and distortion of the case edge.
3. The bottom of the case around the tripod mount has been dished in through a force from below.
4. The EVF backlight high voltage step-up transformer bobbin separated from its plastic support and sheared the fine copper wires.

The camera was otherwise in full working order needing only a clean and some TLC. The casing is aluminium great care is needed when repairing the above detailed damage. Such material will fracture easily. The damage appears to have been the result of the camera being solidly mounted on a tripod or fixed mount, when something heavy fell onto the top of it, casing high forces to travel through the EVF,casing and into the mount. These cameras are used in heavy industry, including the Oil and Mining sectors. Such an accident is why FLIR built these cameras ro be so rugged.

OK, on with Teardown 2 ......

[Fraser]

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The Electric Viewfinder.......

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The damage to the casing.......

[Fraser]

Time for some commentary on the design of the PM570........

AGEMA/FLIR PM570 camera Circa 1997

The Outer Casing

The cameras casing is made from Aluminium and is of the "Palmcorder" format, though somewhat larger and heavier than a camcorder of the period. For a thermal camera of the 1990's, the PM570 was actually quite compact and is very well constructed. Parts of the casing interior show the signs of having been milled out.  A sign of a quality casing. The casing would have been an expensive component to manufacture but it projected the desirable image of a solid professional thermal imaging system that would survive in the Industrial environments for which it was intended. The "PM" prefix in its model ID means "Preventative Maintenance" and this is an area of Industry that makes good use of the capabilities offered by a thermal imaging system.

The aluminium of the casing is coated with a very hard wearing textured paint that may be some form of enamel. The paint does not scratch or come away from the aluminium easily and the cameras are often in good cosmetic condition, even after years of hard use in less than friendly working environments. Such environments include heavy industry, Oil platforms and mines. These cameras from the 1990's and early 2000's are built like Battleships and able to take a pounding. Modern cameras are built ore like a Navy Corvette and need a little more care in their handling

Access to the cameras Battery bay and PCMCIA memory card slot is via a latched metal door that incorporates a weather seal around its perimeter. With the door open, the cameras main PCB can be seen and the camera is vulnerable to dirt and debris infiltration.

On the top of the camera there is a colour LCD electronic viewfinder, external monitor mounting plate and the user keypad. The unit is equipped with a hand grip on the right hand side, with the power button and joystick positioned for easy operation with the thumb. The Joystick is used to navigate the various drop down menus, motorized focus and continuous eZoom functions.

[Fraser]

The electronics package

The Electronics package comprises several PCB's that combine to form a very well engineered thermal imaging system that uses a Microbolometer as its thermal sensor array. The Microbolometer provides 320 x 240 pixels of thermal image data received from the optical block.

The following PCB's are present in the PM570:

1. Main single board computer built around the Motorola MC68340 microprocessor
2. Microbolometer image date processing sub system single board computer built around the 80C186 microprocessor.
3. Power PCB that provides the various supplies needed by the system.
4. Microbolometer PCB to accommodate the microbolometer behind the lens block
5. Battery bay power PCB to support the internal 13.2V Ni-Mh battery
6. Image data Communications PCB (TAXI) providing efficient image transfer to a Windows PC for image analysis etc.
7. Electronic viewfinder PCB set to provide a colour LCD viewfinder.

[Fraser]

The SBC is built around a venerable Motorola MC68K series microprocessor, namely the MC68340. This variant of the MC68K incorporates enhancements to ease integration into a system. It is, in itself a powerful piece of Silicon for 1997. To aid the MC68340 in its duties there are peripheral IC's connected to the data and address busses. Worthy of note are the following:

1. Dallas DS1643 battery supported RTC and SRAM memory
2. CL-PD6722 ISA bus to PC card bridge
3. CY7C109 high speed SRAM
4. T4C4001 fast page DRAM
5. MSM 548262 DRAM
6. MSM 518221 Field Memory
7. ALTERA FLEX EPF8452 PLD
8. ALTERA FLEX EPF8282 PLD
9. PIC 16C55 microcontroller
10. AD7872 14bit ADC
11. BT858 Video Encoder
12. Intel E28F016 Flash memory for firmware
 
These IC's combine with the MC68340 to form the 'brains' of the camera that receives the processed image data from the microbolometer video processor PCB and provides the cameras user ineterface, image display, data storage and measurement capabilities. The fact that a separate 80C186 based video processor SBC is used ensures that the MC68340 is not burdened with the housekeeping needs of the microbolometer. It also facilitates the future refinement of the video processor sub system without having to spin up a new main SBC PCB.

[Fraser]

The Optical Block and lens options

The PM570 is equipped with a sealed, internal motorized focus lens system. That is to say, it is a fixed lens assembly that cannot be changed to provide other fields of view. The lens provides an HFOV of 24 degrees. This is a common and desirable HFOV for industrial preventative maintenance thermal imaging cameras. The lens assembly contains high quality, diamond turned, Germanium lens elements of large diameter. These lens elements were a significant production cost due to their size and quality. Behind the rear lens there is a flat field correction flag that is driven by a powerful solenoid. There is also a motorized high temperature filter that is brought into the optical path when using the higher temperature ranges of the camera. High temperatures are not uncommon in Industry so the PM570 was given the ability to measure temperatures up to 1500 Degrees Celsius.

In order to provide different fields of view, FLIR produced two supplementary lenses that mounted on the camera bayonet mount. The lenses offered 0.45X or 2X magnification, basically doubling or halving the standard field of view. Adding additional lens elements to the optical path did cause an error in camera calibration so a combination of three Hall effect sensors in the camera and small magnets in the supplemental lens mount face provided the camera with the lens identity so that calibration corrections could be automatically employed in the temperature measurement calculations.

[Fraser]

Battery supply

The original AGEMA Thermovision 550 cooled thermal camera required the use of a bulky battery belt to provide for the power hungry cameras needs. The PM570 is a less demanding technology there is no Stirling Mechanical CryoCooler present. That said, the PM570 is a temperature stabilised thermal imaging system that uses a Peltier element in the microbolometer module to maintain a stable die temperature. This temperature stabilisation greatly enhanced the performance and measurement accuracy of the camera, in line with its professional equipment status.  These cameras have to operate in environments that may be both physically and thermally challenging so the temperature stability of the Microbolometer die is important. The initial current draw can be high, but this reduces once the microbolometer die is at the set quiescent state operating temperature. In the absence of the Stirling Mechanical cryocooler, the cameras casing had a large enough void within it to accommodate a 13.2V 2000 mAh Ni-Mh battery pack. This provided 2 hours of continuous operation. Battery changes were simple so extended use could be achieved with the use of multiple battery packs. A battery belt, as used by the THV550 could also be connected to the PM570 for extended use without having to change batteries.

[Fraser]

The Microbolometer and its performance

The PM570 is equipped with a military grade 320 x 240 pixel microbolometer that was highly controlled technology at the time of production. Potential purchasers of the PM570 had to meet the United States security requirements to actually obtain such a camera. The Microbolometer was the first to be used in an AGEMA/FLIR handheld thermal camera and it came onto the market in 1997. User of the venerable AGEMA Thermovision 550 tested the PM570 and, whilst impressed at the uncooled technology, were less impressed with the thermal image produced. We were not used to the levels of noise present in the microbolometers output. There was a Chicken Mesh / Net curtain effect in the images that was quite distracting to users who were accustomed to low noise imagery with no such unusual effects present. That was not to say that the PM570 was dismissed as unsuitable for use. It just took some getting used to after using cooled camera technology. The uncooled Microbolometer removed the need for a noisy Stirling Mechanical cryocooler and its associated high running costs due to a relatively short operational lifespan. The Microbolometer based PM570 did still make noise though...... its FFC flag solenoid is powerful and the operation of the flag can be both heard and felt ! That part of the camera appeared to be over engineered somewhat. The first generation microbolometer used in the PM570 used large 50um pixels and this resulted in a large die and large optics which were expensive to produce. The large pixel size did help with the signal to noise ratio thanks to the good thermal energy collection area. As FLIR had not perfected their noise reduction algorithms, the camera needed all the help it could get from the Microbolometers physics to provide an acceptably low noise image. FLIR greatly improved their noise processing techniques and algorithms in mater firmware versions and new camera releases.

In the following images, note the heat sinking method for the microbolometer Peltier temperature stabiliser. The Peltier element need to sink heat or cold into a large thermal mass in order to do its job efficiently. In the case of the PM570 the Peltier associated thermal energy exits the microbolometers rear face. The energy is transmitted to the cameras aluminium case via a convex/concave coupling system that provides an excellent mechanical and thermal transmission energy path. As can be seen, it is a heavy duty assembly !

[Fraser]

Microbolometer Continued.......