Search results

Search everything Search threads Search blogs
You may enter multiple names here.
  1. G

    VSD as the final element instead of a Control Valve?

    Change the low limit on the flow controller to be equivalent to the minimum motor RPM, eg 40% for 20Hz (50Hz supply). If your motor does not have forced cooling I would typically have 20Hz as minimum, depends on motor design. If flow is possible with the motor not powered you would need an...
  2. G

    First PLC in the project - what's the simplest/cheapest?

    If the PC is such an important part of the process that you need a watchdog from the PC to the PLC, why don’t you do all the automation on a PC?
  3. G

    TCP modbus gateway recommendation for use with TCP Modbus masters with no TCP modbus slave

    Red Lion DSPLE000 protocol converter should do the job, I have used this for converting other protocols and it can also do a lot of different Modbus configurations.
  4. G

    Holykell Ultrasonic Flow Meter

    The ultrasonic flow meter measures velocity, to be able to calculate volumetric flow rate pipe dimensions need to be entered.
  5. G

    Switching device from "Manual mode" to "Auto mode" and vice versa.

    This is a very common way to control motors and other equipment on SCADA systems, custom built by integrators or out of the box PCS7, PlantPAx. It is common to have an Out Of Service/Maintenance mode as well, so if a pump has issues then it is put in OOS mode and can not be changed to Auto...
  6. G

    3 phases inverter output current

    The output current of a three-phase inverter is the current flowing through one phase. The output power of an inverter is: V * I * root 3 * power factor
  7. G

    Dead band in remote speed control

    Start by checking the input to the drive then check the drive parameters. Use a multimeter to check the voltage across the potentiometer terminals at the VFD and at the potentiometer. The wiring could be incorrect, bad connection, wiper on the potentiometer could be damaged or dirty.
  8. G

    3 phases inverter output current

    In this example each line current would be 99 / inverter efficiency. Typical efficiency is 98% (0.98), so around 101 amps. This is at high/full load when line and output voltage are almost the same.
  9. G

    3 phases inverter output current

    Yes JeffersonAirplane the source can have a different number of lines than the load, small inverters with 1 phase in and 3 phase out, eg 230V single phase in 230V three phase out. Inverters are generally variable voltage and frequency so at low loads, when output voltage is well below line...
  10. G

    Need some help with ladder diagrams

    PLC ladder programs are processed left to right, top to bottom, this needs to be understood by PLC programmers so all intended operations occur. It also needs to be understood when the HMI writes to the PLC, generally this is in between each scan of the program but not with all PLC/HMI systems
  11. G

    Need some help with ladder diagrams

    Read the specification to work out what is required, basically this could be one timer that is self resetting, started by the start button and stopped and reset by the stop button. All the lights can be controlled by comparing the elapsed time of the timer to what is required in the specification.
  12. G

    ABB PM583 Pulse Counter

    The DC523 card has two terminals that can be configured as a fast counter which can handle up to 50kHz, video on YouTube
  13. G

    Symbology for Speed Controller on Pneumatic Valve

    There are different variations of pneumatic speed controllers so there is not one symbol that suits all, see the supplier catalog of the particular flow controller you want to use for the symbology
  14. G

    New to PLCs

    1. Yes, a safety-rated PLC can replace safety relays, including pulse testing of dual channel inputs. Depending on your requirements on the output side you may need additional relays compared to a safety relay for the loads you are isolating. 2. Generally there are approved program blocks that...
  15. G

    VFD output voltage indicator

    Make sure the specifications of the voltage sensing relay is suitable for your application, check with relay supplier if unsure. The VSD will have a high frequency output, probably 4kHz
  16. G

    VFD output voltage indicator

    A voltage sensing relay rather than a simple relay: https://broycecontrol.com/product/lmcvr-500v/
  17. G

    Flow Balancing Valves - control strategy

    If you need more ideas then describe the process more before the flow control valves, ideally P&ID sketch. What supplies the fluid to the control valves, pump? gravity?
  18. G

    Do we need Braking resistor with VFD?

    AndreyG your conclusion is correct, low inertia loads generally don’t need a brake resistor on VFD. Only time you may need one is if you ramp down very quickly, for your application you could coast to stop rather than ramp down.
  19. G

    How to read extended Registers?

    It looks like you’re DCS can only handle “original” Modbus range - 40001 to 49999, not “extended” Modbus range - 400001 to 465535
  20. G

    PLC - Measurement data over RS 232

    You are correct mairothia your PLC has RS-232 ports, don’t get misdirected by some vague thoughts about RS-485. If you google “slc-500 write ascii” you should come across an example which should be very similar for Micrologix as both use Logix500 software. You can send ASCII data via the RS-232...
Top