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  1. C

    Two wire instruments powered using two pair cable

    It sounds like this installation resulted in the positive and negative wires not being twisted together, making them more susceptible to common-mode noise.
  2. C

    Commuincating with Laser Caliper (Laser Online LST-25 JIB)

    Looks like this has come up before: https://m.control.com/thread/1552329380
  3. C

    Radar Level Dielectric Constant

    Some radar transmitters have a general media dielectric parameter that affects the transmitter's sensitivity (e.g., lower dielectric results in higher sensitivity so that the transmitter can detect smaller signals). There may also be a separate parameter for the dielectric of the upper...
  4. C

    Troubleshouting Foundation Fieldbus

    Does the model number of your device include "PA"? If so, you likely have a Profibus model, which will not communicate on an FF network.
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    Differentiation Between Profibus Class 1 and Class 2 Master

    There's a good description here: https://www.automation.com/library/articles-white-papers/fieldbus-serial-bus-io-networks/introduction-to-profibus-dp
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    Magnetrol E3

    "SecFltLo" indicates that the readings from the LVDT are lower than expected. If the E3 (and its displacer) is intended to measure Interface level, an empty chamber could result in "SecFltLo" indication. Otherwise, there could be something wrong with the range spring, displacer, or...
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    Modbus RTU Help

    According to the Modbus specification, up to 247 slaves can exist in a network. However, that's a logical limit, there are electrical considerations. The specification also states, "A figure of 32 devices is always authorized on any RS485-MODBUS system without repeater." The actual number...
  8. C

    Magnetrol E3

    The message indicates that the position of the stem is too high, as sensed by the transmitter's electronics. The stem is connected to a range spring which applies force upwards and the displacer which pulls down due to its weight, counteracting the spring. If the displacer were to become...
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    4-20mA to 10-24VDC Foundation Fieldbus Converter

    Two that I am aware of: http://www.smar.com/en/product/if302-if302-triple-channel-current-to-foundationtm-fieldbus-converter http://www.microcyber.cn/fieldbusconverter/191.html
  10. C

    Flow Transmitter Calibration (Micro Motion EMERSON)

    Because this is a Foundation fieldbus device, you likely need to change the Output scaling in the AI block that you are using. According to the manual, "You can change the output scale only with a fieldbus host". Are you sure that your DCS does not provide access to transmitter AI blocks?
  11. C

    Motor Selection Help

    I would use a "gearhead" motor for an experiment like you describe. You may want something with adequate power, but not enough to be dangerous... For example: http://www.mpja.com/12VDC-30-RPM-Gearhead-Motor/productinfo/32204+MD/
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    Virus infection via Modbus

    For a control system to be infected via Modbus, the system would have to have features such that the control program or related software can be changed using Modbus registers. I would be surprised if there are control systems that are programmable in a significant way via a Modbus interface...
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    Fieldbus (H1) to RS232 Converter

    Softing has a Modbus to Foundation Fieldbus gateway [e.g., FIM-110 FF] that provides an RS-232 interface.
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    Hover Training Sensor

    Interesting challenge! Due to the narrow width tolerance for your application, consider a laser rangefinder. Possibly something like that shown here: https://www.parallax.com/product/28043 could work.
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    Concrete Spreader Control

    Interesting machine! Perhaps it would help to start the dispensing in the middle of the slab and after the trolley is already moving.
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    A Question for All - RS232 Serial Port Communication

    I have had success using USB to serial converters manufactured by FTDI. When these are plugged into a PC they are assigned a port number, which could be an annoying value such as COM23. Using Device Manager you can find the number assigned to the USB Serial Port and force it to something...
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    Difference Between Profibus DP and Profibus PA

    PROFIBUS PA is a fieldbus [specified in IEC 61158-2] which typically supplies power and transmits communication digitally on a single pair of wires. Electrical signal levels and data rates are different than those of PROFIBUS DP. To connect a PROFIBUS PA device to a PROFIBUS DP network, a...
  18. C

    How HART Signal of DAC Can Be Differentiated from Loop Current?

    Differentiating the HART FSK signal on the loop is the HART modem's job (the AD5700 device, in this example). The HART modem converts the frequency information to digital ones and zeroes, a 1.2 kHz signal represents a digital 1. Typically, a HART modem is connected to a microcontroller or...
  19. C

    Guided Wave Radar Level Transmitter

    I don't know much about Triconex systems, but I imagine that they may utilize only the loop current, for example, reacting to out-of-range loop current values (e.g. less than 3.8 mA, or greater than 21 mA). Transmitters such as E+H's can output a low (less than 3.8 mA) or high (greater than...
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    Guided Wave Radar Level Transmitter

    It's unlikely that there are any radar transmitters that do not have a CPU (microcontroller). Processing radar signal information essentially requires computation. Incidentally, "smart" is sometimes used to refer to a device's ability to communicate with a digital protocol such as HART...
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