Repurposing a solenoid array to communicate with arduino

[mforbes]

I harvested a PCB from a tecan cavro multichannel pump (pdf manual attached). I want to control just the solenoid 3 way valves via arduino. One PCB seems to control all 8 solenoids which are 24VDC (current I'm not so sure). From what I can see two darlington transistors control 4 valves each. My question is, how would I go about working out which of the pins to provide the 24VDC to and which pins I can switch the solenoids with?

I've attached an image of the PCB

 

[kellys_eye]

It's not RS232 controlled. It's a 'simple' serial data stream (clock/data and maybe reset) fed straight to the shift registers.

Get the shift register datasheet and you will be able to trace the relevant signal (pins) lines back to the box connector.

The shift registers will (probably) work from 5V so there will be a pin for that supply as well as whatever is used for the solenoids. The solenoid supply voltage could be 'anything' as the supply line will be switched via the relevant drive transistors that themselves will be controlled from the output of the shift registers.

Need better (closer) pictures of the boards

 

[mforbes]

It's not RS232 controlled. It's a 'simple' serial data stream (clock/data and maybe reset) fed straight to the shift registers.

Get the shift register datasheet and you will be able to trace the relevant signal (pins) lines back to the box connector.

The shift registers will (probably) work from 5V so there will be a pin for that supply as well as whatever is used for the solenoids. The solenoid supply voltage could be 'anything' as the supply line will be switched via the relevant drive transistors that themselves will be controlled from the output of the shift registers.

Need better (closer) pictures of the boards

Hi!,
Thank you for the reply, I've been wondering how to do this for a while now. So, I know the solenoids are 24VDC so I guess the input to the board should be that. The shift registers are these:

TPIC6B595 data sheet, product information and support | TI.com

TI’s TPIC6B595 is a 8-bit shift register with 150mA/ch. Find parameters, ordering and quality information

www.ti.com

I need to do some reading around how these registers can work with my arduino, but if I can provide the 24V first then I can work out the pins one by one. I'll try and get better pictures and remove the connector to see the pins.
Thanks

 

[kellys_eye]

but if I can provide the 24V first

The shift registers run at 5V (see the datasheet) so the board won't work unless you provide BOTH supplies to it.