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DRV110EVM: DRV110EVM: Help controlling solenoid

Prodigy 40 points

Replies: 8

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Part Number: DRV110EVM

I am using a DRV110EVM evaluation board to energize a 12V (29 ohm) solenoid.
I am trying to use the on-board oscillator and peak/hold to cycle my solenoid, but I cannot get it to consistently actuate.
If I adjust pots, I can trigger a single pickup and release but no continuous cycling.

Settings:

- JP1, JP2, JP6 closed (with shorting shunts),

- JP3, JP4, JP5, JP8, JP7, JP9 open

- Pot R4 Peak, R5 Hold, and R6 (OSC) varied without cycling my solenoid

- 12 VDC supply connected to P1-1 and P1-3

- 12V (29 ohm) solenoid coil connected to P1-2 & P1-4

I only get momentary solenoid actuation, not continuous cycling.

Thanks fore your help,

Ken

  • Hi,

    I have notified our expert regarding this topic. Please expect a response by 3/15/19.

    Thanks,
     Costin

  • In reply to Costin Cazana:

    Hi Ken,

    You need to toggle Enable Pin, the rising edge starts the cycle:
    -Enable On
    -Ipeak on with 100mS duration set by Ckeep:C3=1uF
    -Ihold for the rest of the On time
    Connect to TP3 or the active side of JP9 a 1Hz 0-3V pulse generator

    Regards,
    Costin
  • In reply to Costin Cazana:

    I'm using the DRV110EVM setup above with a TTL signal generator (1 Hz) into the Enable pin.    I'm trying to drive a bank of six 12vdc solenoid valves  (29 ohm each) connected in parallel  (4.8 ohm to the DRV110).  I can barely drive one valve with 14vdc supply.   I tried using a Solid State Relay (SSR) but its turn-on and turn-off speed is too slow to effectively pass the PWM pulses.

    What must I do to drive at least  two or three of my solenoid valves?  I have attached images of my setup.

    Is it possible to use a faster SSR to drive the bank of six valves?

    Thanks for your help,

    Ken

      

  • In reply to Ken S:

    Hi Ken,

    First we need to find out what are the valve requirements: Ipeak, Ihold and Tkeep.
    The max Ipeak is < Vs/29ohm, that's less than 0.4A for Vs=12V
    First experiment I'll recommend is to find out Ipeak needed:
    1) Set Vs=14V
    2) Set Rpeak=150kohm to get Ipeak=0.4A
    3) Set Enable freq >5Hz to get Enable time <100mS, only Ipeak will be on without Ihold.
    If it doesn't work, increase Vs and Ipeak up to 0.85A without changing Tkeep. Also you can increase Tkeep( increasing Ckeep) with 0.4A<Ipeak<0.85A
    After finding out valve Ipeak and Tkeep, next step is to find out Ihold needed.
    1) Enable_Ton> Tkeep
    2) Adjust Ihold with Rhold, the max Ihold you can is 0.15A with EVM Rsense=1ohm.
    If more Ihold current is needed you'll have to lower Rsense, my suggestion is Rsense=0.5ohm

    After one valve works, Rsense needs to be adjusted to drive more valves
    Rsense=previous Rsense/# valves

    Regards,
    Costin
  • In reply to Costin Cazana:

    Hi Ken,

    Do you have any updates? One solenoid works with Ipeak=0.4A( Rsense=1ohm, Rpeak=150kohm)?
    If you need to increase Vs >14V, series resistance is needed since DRV110 input zener turns on. Use EVM R3 as input current limiting resistor.
    For your application SSR is not needed, the EVM FET has the required current capabilities.

    Regards,
    Costin
    Costin
  • In reply to Costin Cazana:

    Costin,

    Sorry for the late reply, very busy here.  I did check a single valve connected to the DRV110EVM.

    I adjusted Rpeak = 150kohm and Vs=14vdc.

    Using a Fluke 179,   I measured Ipeak = 0.38A and Ihold = 0.057A for a single valve.

    Questions:

    - Now should I need to reduce Rsense?  I will need to order a 1ohm resistor (in parallel to existing sense resistor).  Can I install a pot?

    - Will the final pcba setup allow me to use one valve or six valves without adjusting Rsense or pts?

    Thanks for your help,

    Ken

  • In reply to Ken S:

    Hi Ken,

    For Rsense= 1ohm, the max Ipeak and Ihold is not enough to drive multiple solenoids:

    Rsense range:

    50mV/Ihold<Rsense<150mV/Rsense

    300mV/Ipeak<Rsense<900mV/Ipeak

    Pot is ok, the only issue I can think about is the price

    Regards,

    Costin

  • In reply to Costin Cazana:

    Hi Ken,

    I'll close this thread, please open a new one when you'll have new bench results.

    Thank you,
    Costin

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