Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  • Users: techzone12
  • Order by date
  1. techzone12

    KW metering

    Ok I am finding more info on this. The meter is made by GE, model# VW63S. Line K is attached to 2 single-pole single-throw switches "Y" and "Z". "Y" and "Z" open and close as the disk rotates. As the meter rotates in one direction, Y closes then Z closes, then Y opens, then Z opens. When it...
  2. techzone12

    KW metering

    For a KWH meter: What does KWC pulse value of 10 mean? What does RVA pulse value of 4.8 mean? How can the above values be used to calcualte KW?
  3. techzone12

    KW metering

    We have an old KWH meter that has been isnatlled more than 12 years ago. I was told that it's not easy to access the meter to look at it. But I was tasked to figure out if the exisiting calculations are correct for KW values. The meter measures KWH. Every so many KWH it create a pulse which is...
  4. techzone12

    Modbus RS232 to RS485 converted

    I have a PLC that talks Modbus. I am going to use Modscan software running on my laptop (master), to pull data form the PLC (for initial testing purposes). The PLC have 3 terminal blocks for communications (+,- and shield). In order for me to connect from my laptop comports (comm1, RJ485 to USB)...
  5. techzone12

    SCADA Vs BMS (BACNET)

    Sorry, I meant to say DDC (Direct Digital Control)....
  6. techzone12

    Using Hypertermial to test and trouble-shoot serial communications?

    What about RS485, can I use Hyperterminal to anlayze the data, or should I use a different analyzer. Some one was telling me to use "HDD serial monitor". Say the PLC is talking Modbus RTU (using RS485), and I just want to make sure that I can comminicate with the device and maybe pull one...
  7. techzone12

    SCADA Vs BMS (BACNET)

    I would vote for a DCC system, it's cheaper and it does the job. You won't be compromising on the quality if you choose the right BMS integrator. HVAC sytems don't normally require high processing speed, which is usually provided by PLC's. In addition to that, DCC BMS systems are easier to...
  8. techzone12

    Using Hypertermial to test and trouble-shoot serial communications?

    If I Have a computer running Hyperterminal, and it's connected to the controller using serial commport-1. How can I use hyperterminal to test and trouble-shoot the serial communication. Can some one point me to a manual or a tutorial on how to use Hyperterminal to test serial communications...
  9. techzone12

    Control Transformer for DDC control

    We are installing VAV controllers in the ceiling plenum of a building. The controllers require 24V and each one is 10 VA rated. How big of a 24V transformer can we install in the ceiling plenum to provide power to the controllers? What are the limitations by the NEC code? If the controllers, as...
  10. techzone12

    Differential Pressure to GPM conversion

    Bernoulli: "Pressure Energy" + "Kenetic Energy per unit volume" + "potential Energy per unit volume" = constant P/? + V2/2 + gh = Const Where V2 is "V square".
  11. techzone12

    Differential Pressure to GPM conversion

    Thanks guys!
  12. techzone12

    Differential Pressure to GPM conversion

    What is the formula that connects differential Pressure (inwc) and water Flow (GPM) in a pipe. Thanks
  13. techzone12

    IIM board (Input Interface Module)

    When wiring input sensors as inputs to digital controllers, I sometimes see that a "IIM board" being used. My understanding is that they are used for electrical isolation between field devices and the controller. My question is , when is it a must, and when is it an option? Or is it an extra...
  14. techzone12

    Energy Saving Sequence

    Thanks for the feedback. Another idea that came to mind, is to reset VAV temp setpoints when the KW peak is approached. Since peak KW will cost much more $$.
  15. techzone12

    Energy Saving Sequence

    I have a large commerical office building with a fully auomated systems. The HVAC (BAS) system is controlled by DCS controllers. It has multiple AHU units, VAV units, Chillers, etc. I am trying to come up with sequences to save energy. We are already using economizer mode (free fresh air), when...
  16. techzone12

    energy saving sequence of operation

    I am not sure if this is the right place to post this questions? But any way.. I have a large commerical office building with a fully auomated systems. The HVAC (BAS) system is controlled by DCS controllers. It has multiple AHU units, VAV units, Chillers, etc. I am trying to come up with...
  17. techzone12

    RS485 terminating resistor

    I know the answer might be very involved, but I cann't help but asking why ? Why is a bigger resistor is unable to absorb (dissipate) all the induced enegry by the signal? Thanks
  18. techzone12

    RS485 terminating resistor

    Thank you for the valuable feedback. It is starting to make sense to me. I have a question however: If the purpose of using the resistor is to absorb the signal energy on the transmission line, what happens if someone install a resistor (at the end of the line) with higher value that the...
  19. techzone12

    RS485 terminating resistor

    Recently I installed a "RS485" connection between our controller and a third party controller. It was specified that one must connect terminating resistor on each end of the RS485 loop (because it's a long run). It says that resistor is designed to match the electrical impedance characteristic...
  20. techzone12

    Control Circuits Design Book

    I am a mechanical engineer, and I work in the building automation industry. I often come across many engineering disciplines. I have been, for the most part, on the software side (programming of controllers and IT) for quite a while now. I would like to learn more about the hardware (field...

Part and Inventory Search

Back
Top