Piezoelectric Stage Development Evolution, Part C

mawyatt · Post by **mawyatt** » Sat Nov 23, 2019 7:28 pm

Part C is the Piezo Controller for the OEM P603K Driver/Amp

After starting the Custom Closed Loop Controller/Driver/Amp development some surplus Physik Instrumente OEM P603K Driver/Amp and Stages came available, later some of the surplus OEM P603K Driver/Amps came available. All these at very attractive prices on eBay.

Since the development for the Custom Close Loop Controller/Driver/Amp was so involved and the likelihood of something not working as planned high since no information was available we decided to run a parallel effort trying to develop a Controller for the OEM P603K Driver/Amp, sort of a Plan C just in case Plan B didn't work.

Because of the lack of information we had to figure out how to interface with the P603K Controller and what signals were required and how things worked. This took some time and a few beers to figure out, then the risky part of adding a supply voltage and seeing if anything smoked

I noticed that after quite a few beers everything became crystal clear, but then I forgot everything by time the beers wore off

Well, nothing smoked and we were able to figure out what the connectors were and how to interface with them. The external interface connector had to be removed as did the power connector, and replaced with a more standard available HX type connector which has the same pin pitch of 0.1".

The external interface connector has 4 wires which are Ground, Input, Output Voltage/100 and Position Output. Input ranges from 0 to +10.000V for full scale piezo stage displacement, Output Voltage /100 reads the piezo stage driver output voltage from -0.3 to +1.3V for a piezo driver -30 to 130 Volt range and Position Output is 10.00 volts for full scale stage position, linear with stage position.

The custom Controller was developed to allow complete isolation from the RPi interface, just like the Custom Closed Loop Controller/Driver/Amp. Dual switch mode power supplies create +-20V which are linear regulated to +-15V, +5V, and +5.000V Reference all from a +12VDC Power supply input at <1/2A which is also filtered and routed to the OEM DP603K Driver/Amp power connector.

Like the Custom Closed Loop design this includes a 12 Bit Core DAC, which can be augmented to 20 Bits, has provisions (Socket) for 16 Bit Core DAC and has a 16 Bit ADC with PGA with a socket for an 18 Bit ADC with PGA.

The reference was chosen to be 5.000V rather than 4.096V because the OEM P603K requires +10.000V input for full scale, thus a 2X amplifier follows the DAC output. Since +10 is required we decided upon +-15V main analog power rather than +-9V used in the Custom Closed Loop design. Provisions were included to allow an external Pot to control the output stage directly or superimposed upon the DAC control signal like the Custom Closed Loop (the OEM P603K has no provisions for this feature).

The Controller PCB was designed to mount directly on top of the OEM P603K Driver/Amp PCB Controller.

These work well with other P603K piezo stages but not with the P601K stage because the initial P601K strain gauge offset is too high. Later we were able to get these to work with the P601K stage by adding an offset correction adjustment to the strain gauge cable.

Initial testing also reveled that the Custom Controller for OEM P603K Driver/Amp with P603K stage is working amazingly well like the Close Loop Controller/Driver/Amp.

Bottom line is both the Custom Closed Loop Controller/Driver/Amp and the Custom Controller for the OEM P603K Driver/Amp are working very well indeed

More testing is required but all the hard work has definitely paid off

Anyone want to help??

Best,

P603K Stage

Macro_Cosmos · Post by **Macro_Cosmos** » Fri Nov 29, 2019 11:34 pm

It was a nice read, I appreciate the work and effort, and the beers that went into this! PI products are astronomically priced if purchased new, glad there's some surplus stuff. I'll read some other development posts while I'm still on the grid. Thanks!

mawyatt · Post by **mawyatt** » Sat Nov 30, 2019 7:24 am

You are quite welcome mate

Agree, the PI devices are very expensive, generally slated for serious lab or semiconductor use. The devices I've found on eBay were in good condition and work extremely well, especially with closed loop operation.

It's easy to talk about sub-micron stacking, but one usually doesn't really know if the stage is actually moving at the commanded increments. This might not be an issue with non-uniform stacks unless the stage "hangs and jumps" a little and the jump exceeds the DOF.

After some initial tests with the PI devices in Closed Loop configuration, I'm convinced that these can reliably perform at sub-micron, even nanometer levels. Of course you'll need a good controller to do this, which apparently we now have

Cheers,

mawyatt · Post by **mawyatt** » Tue Dec 03, 2019 2:26 pm

Update on the Custom Controller for the PI P603K Driver/Amp. As mentioned in "Part B", the 16 bit DACs have been received and driver routines developed and tested. These have been applied to the P603K Controller as well as the Full Custom Controller/Driver/Amp in part B.

Here's some notes on the P603K Controller.

A) Raspberry Pi Standard 40 Pin Connector Header
B) Red LED indicate RPi is connected properly and powered
C) +20V TP
D) +12V Filtered Output Power for PI P603K Driver/Amp
E) Input Power Connector, +12V at < 1/2A
F) +12V Blue LED
G) Power Ground Pin
H) Ground Jumper, Connects Analog to Power Ground bypassing isolation resistor R11
I) 16 Bit DAC Address Select
J) Fine DAC Trim, for 2nd 12 bit DAC trim. Used to augment 12 or 16 bit DACs to ~20 bits, or for linearity correction (lookup table)
K) 16 bit DAC Socket
L) 16 Bit ADC Module
M) 18 Bit ADC Socket
N) 16 bit ADC Address Select
O) External Pot Header, Test Point VPOT is just above. For Manual Stage Movement superimposed with DAC command position
P) External Pot Connector
Q) Enable Read Piezo Output Voltage/100 Jumper
R) Enable Read Piezo Stage Position Jumper
S) ADC Position Trim
T) Analog Ground
U) Offset DAC Control Voltage Trim
V) DAC Trim
W) DAC Output Connector
X) DAC Output Header
Y) Analog Interface Connector, to PI603K Analog Input & Output
Z) Analog Interface Header
AA) Control Voltage Output TP
BB) Voltage Reference Trim, 5.000V
CC) Raspberry Pi "0" volts jumper, shorts R1/R43
EE) +5V Test Point
FF) Reference Voltage TP
GG) -20V TP
HH) DAC TP
II) -VEE TP, -15V
JJ) +VCC TP, +15V
KK) Fine DAC TP, 2nd 12 bit DAC for ~20 bit augmentation of 1st 12 bit DAC or 16 bit DAC, can also be linearity correction (table lookup)
LL) +20V Active Jumper
MM) VCC Selection Jumper
OO) Fine Trim Active Jumper
PP) RPi GPIO IIC Isolation
QQ) 100uH Inductor for -20V, works with U9 & D5
RR) 100uH Inductor for +20V, works with U10 & D4
SS) Large Filter Caps
TT) +12 Input Resettable Fuse

Other notes:

U5 & U4 12bit DACs
U6 Voltage Reference
U12 +5V Regulator
U7 +VCC Regulator
U8 -VEE Regulator

Best,

Mike

mawyatt · Post by **mawyatt** » Wed Dec 04, 2019 7:19 am

Here’s the Physik Instrumente Closed Loop Controller/Driver/Amp equivalent to our Custom Controller with the OEM P603K Driver/Amp development. Should have similar performance at a lower cost.

https://www.physikinstrumente.store/us/ ... ontroller/

PI Closed Loop Systems with Controller/Driver/Amp & Stage. Our Developed Controller with OEM P603K Driver/Amp and OEM P603K Stage should have similar performance, but at a much lower cost!!

https://www.physikinstrumente.store/us/ ... tem-100-m/

Best,

Mike