Emerson Rosemount 248 Reference Manual
  1. Manuals
  2. Brands
  3. Emerson Manuals
  4. Transmitter
  5. Rosemount 248
  6. Reference manual
Emerson Rosemount 248 Reference Manual

Emerson Rosemount 248 Reference Manual

Temperature transmitter
Hide thumbs Also See for Rosemount 248:
Table of Contents

Advertisement

Quick Links

See also: Reference Manual
Reference Manual
00809-0100-4825, Rev DA
May 2019
™
Rosemount
248 Temperature Transmitter

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the Rosemount 248 and is the answer not in the manual?

Questions and answers

Related Manuals for Emerson Rosemount 248

Summary of Contents for Emerson Rosemount 248

  • Page 1 Reference Manual 00809-0100-4825, Rev DA May 2019 ™ Rosemount 248 Temperature Transmitter...
  • Page 2 Using non-nuclear qualified products in applications that require nuclear-qualified hardware or products may cause inaccurate readings. ™ For information on Rosemount nuclear-qualified products, contact an Emerson Sales Representative. WARNING Failure to follow these installation guidelines could result in death or serious injury.

  • Page 3: Table Of Contents

    3.1 Safety messages..........................29 3.2 Commissioning..........................29 3.3 AMS Device Manager........................30 3.4 Field Communicator........................31 3.5 Multidrop communication......................42 3.6 Rosemount 248 Configuration Interface specifications..............43 Chapter 4 Operation and Maintenance..................45 4.1 Safety messages..........................45 4.2 Calibration............................45 4.3 Transmitter-sensor matching......................47 4.4 Switching HART Revision........................
  • Page 4 Contents Reference Manual May 2019 00809-0100-4825 A.1 Product Certifications........................59 A.2 Ordering Information, Specifications, and Drawings..............59 Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 5: Chapter 1 Introduction

    Acceptance of inputs from a wide variety of RTD and thermocouple sensors • Configuration using HART protocol • Electronics encapsulated in epoxy and enclosed in a plastic housing, making the transmitter extremely durable and ensuring long-term reliability Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 6 HART devices. To access this functionality, the new device driver must be downloaded. It is recommended to download the new device driver to ensure new functionality. Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 7: Product Recycling/Disposal

    Reference Manual Introduction 00809-0100-4825 May 2019 Product recycling/disposal Recycling of equipment and packaging should be taken into consideration and disposed of in accordance with local and national legislation/regulations. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 8 Introduction Reference Manual May 2019 00809-0100-4825 Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 9: Chapter 2 Installation

    Use extreme caution when making contact with the leads and terminals. Confirm HART revision capability ® If using HART based control or asset management systems, confirm the HART Protocol capability of those systems prior to transmitter installation. Not all systems are capable of Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 10: Switch Hart ® Revision Mode

    Commissioning. 2.4.3 Mechanical Location When choosing an installation location, take into account access to the transmitter. Special mounting Special hardware is available for mounting a Rosemount 248 head mount transmitter to a DIN rail. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 11 Figure 2-1 provides an example of the relationship between transmitter housing temperature rise and extension length. Figure 2-1: Rosemount 248 Transmitter Connection Head Temperature rise vs. Extension Length Extended ranges available with BR5 and BR6 option codes. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 12 (moves 85 to 55 °C), or 30 °C. In this case, an extension of 100 mm meets this requirement, but 125 mm provides a margin of 8 °C, reducing any temperature effects in the transmitter. 2.4.6 Installation Flowchart Figure 2-2: Installation Flowchart Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 13: Mounting

    To a DIN rail using an optional mounting clip 2.5.1 Mounting a Rosemount 248H to a DIN rail Procedure • To attach a head mount transmitter to a DIN rail, assemble the appropriate rail mounting kit (part number 00248-1601-0001) . Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 14: Installing The Transmitter

    Installation Reference Manual May 2019 00809-0100-4825 Figure 2-3: Assembling Rail Clip Hardware to a Rosemount 248 A. Mounting hardware B. Transmitter C. Rail clip Installing the transmitter ™ The Rosemount 248 can be ordered assembled to a sensor and thermowell or as a stand- alone unit.
  • Page 15 Example Figure 2-4: European and Asia Pacific installation diagram A. Rosemount 248 transmitter B. Connection head C. Thermowell D. Transmitter mounting screws E. Integral mount sensor with flying leads F. Extension Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 16 C. Standard extension D. Universal head E. Conduit entry Rail mount transmitter with integral mount sensor The least complicated assembly uses: • an integral mount sensor with terminal block • an integral DIN style connection head Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 17 • a standard extension • a threaded thermowell Refer to the appropriate Product Data Sheet regarding Emerson temperature elements for complete sensor and mounting accessory information. To complete the assembly: Procedure 1. Attach the transmitter to a suitable rail or panel.
  • Page 18 • a union and nipple extension assembly • a threaded thermowell Refer to the appropriate Product Data Sheet regarding Emerson temperature elements for complete sensor and mounting accessory information. To complete the assembly: Procedure 1. Attach the transmitter to a suitable rail or panel.

  • Page 19: Multichannel Installations

    Standard saturation levels: • 3.90 mA on the low end • 20.5 mA on the high end NAMUR compliant saturation levels: • 3.80 mA on the low end • 20.5 mA on the high end Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 20: Wiring

    3. Tighten the terminal screws. 4. Reattach and tighten the cover (if applicable). All connection head covers must be fully engaged to meet explosion-proof requirements. 5. Apply power (see Power supply). Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 21 250 and 1100 ohms load for communications. 2.9.1 Sensor connections The Rosemount 248 is compatible with a number of RTD and thermocouple sensor types. Figure 2-10 shows the correct input connections to the sensor terminals on the transmitter.
  • Page 22 ± 1.0 Ω in reading per ohm of unbalanced lead wire resistance (Unbalanced lead wire resistance = maximum imbalance between any two leads.) 2-wire RTD 1.0 Ω in reading per ohm of lead wire resistance Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 23 Pt100 3-wire RTD: Lead wire imbalance seen by the transmitter = 0.5 Ω • Pt100 2-wire RTD: Lead wire resistance seen by the transmitter = 150 m × 2 wires × 0.025 Ω/m = 7.5 Ω Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 24: Power Supply

    The best place to ground the loop is at the negative terminal of the power supply. Do not ground the current signal loop at more than one point. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 25 1. Connect signal wiring shield to the sensor wiring shield. 2. Make sure that the two shields are tied together and electrically isolated from the transmitter housing. 3. Ground shield at the power supply end only. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 26 3. Do not connect the signal wiring shield to the sensor wiring shield. 4. Ground signal wiring shield at the power supply end. Example 1. Transmitter 2. Sensor wires 3. DCS Host System 4. Shield ground point Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 27 3. Do not connect the signal wiring shield to the sensor wiring shield. 4. Ground signal wiring shield at the power supply end. Example A. Transmitter B. Sensor wires C. DCS Host System D. Shield ground point Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 28 Installation Reference Manual May 2019 00809-0100-4825 Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 29: Chapter 3 Configuration

    Commissioning consists of testing the transmitter and verifying transmitter configuration data. The Rosemount 248 can be commissioned before (off-line) or after (on-line) installation. During on-line configuration, the transmitter is connected to a Field Communicator and data is entered into the working register of the communicator and sent directly to the transmitter.

  • Page 30: Ams Device Manager

    1. Right click on the device and select Configuration Properties from the menu. 2. From the bottom of the screen, select Apply. 3. When the Apply Parameter Modification screen appears, enter the desired information and select OK. 4. After reading the warning provided, select OK. Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 31: Field Communicator

    When using a Field Communicator, configuration changes must be sent to the transmitter using the “Send” key (F2). For more information regarding the Field Communicator, see the Field Communicator User Guide. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 32 Options listed in bold type indicate a selection provides other options. For ease of operation, changing calibration and setup, such as sensor type, number of wires, and range values, can be completed from several locations. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 33 Reference Manual Configuration 00809-0100-4825 May 2019 ® 3.4.2 HART 7 menu tree Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 34 3.4.5 Configuring the transmitter The Rosemount 248 must be configured for certain basic variables to be operational. In many cases, these variables are pre-configured at the factory. Configuration may be required if the transmitter is not configured, or if the configuration variables need revision.
  • Page 35 Damping value = At the time the damping time constant is set, the transmitter output is at 63 percent of the input change and continues to approach the input according to the damping equation above. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 36 3. Enter the total measured resistance of the two RTD leads at the 2-Wire Offset prompt. Enter this resistance as a negative (–) value to ensure proper adjustment. The transmitter adjusts its temperature measurement to correct the error caused by lead wire resistance. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 37 Field Communicator. Sensor serial number The Sensor S/N variable provides a location to list the serial number of the attached sensor. It is useful for identifying sensors and tracking sensor calibration information. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 38 After completing the test procedure, the display returns to the loop test screen and another output value can be chosen. Master reset Master Reset resets the electronics without actually powering down the unit. It does not return the transmitter to the original factory configuration. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 39 The Active Calibrator Mode must be disabled before returning the transmitter to the process to ensure that the full diagnostic capabilities of the Rosemount 248 are available. Disabling or enabling the Active Calibrator Mode will not change any of the sensor trim values stored in the transmitter.
  • Page 40 The threshold value of the Rosemount 248 should be set at a level allowing for normal range of process temperature fluctuations; too high and the algorithm will not be able to filter out intermittent conditions;...
  • Page 41 For users of the Rosemount 248 that desire a more immediate open sensor detection, the Open Sensor Holdoff option can be changed to a fast setting. On this setting, the transmitter reports an open sensor condition without additional verification of the open condition.

  • Page 42: Multidrop Communication

    Note Rosemount 248 Transmitters are set to address 0 at the factory, which allows them to operate in the standard point-to-point manner with a 4–20 mA output signal. To activate multidrop communication, the transmitter address must be changed to a number between 1 and 15.

  • Page 43: Rosemount 248 Configuration Interface Specifications

    Damping • Alarming Parameters 3.6.2 Configuration hardware The Rosemount 248 Configuration Interface has three hardware options as follows: Software only Customer must provide appropriate communications hardware (modem, power supply, etc.) Serial HART modem and software Serial HART modem. Customer must provide separate loop power supply and resistor.
  • Page 44 2. Set up configuration system hardware: a) Hook up the transmitter and load resistor (250–1100 ohms) wired in series with the power supply. (The Rosemount 248 device will need an external power supply of 12–42.4 Vdc for configuration) b) Attach the HART Modem in parallel with the load resistor and connect it to...

  • Page 45: Operation And Maintenance

    In operation, the transmitter uses this information to produce a process variable output, in engineering units, dependent on the sensor input. Calibration of the Rosemount 248 may include the following procedures: Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 46 Sensor trimming is suitable for validation procedures or for applications that require calibrating the sensor and transmitter together. To perform a sensor trim with a Rosemount 248: Procedure 1. Connect the calibration device or sensor to the transmitter. Refer to Figure 2-10 inside of the transmitter terminal side cover for sensor wiring diagrams.

  • Page 47: Transmitter-Sensor Matching

    Callendar-Van Dusen constants. When ordered from Emerson Process Management, sensors with Callendar-Van Dusen constants are NIST-traceable. The Rosemount 248 accepts Callendar-Van Dusen constants from a calibrated RTD schedule and generates a special custom curve to match that specific sensor Resistance vs. Temperature performance.
  • Page 48 The following input variables, included with specially-ordered Rosemount temperature sensors, are required: α [t – δ(0.01t-1)(0.01t) – β(0.01t – 1)(0.01t) R0 = Resistance at Ice Point Alpha = Sensor Specific Constant Beta = Sensor Specific Constant Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 49: Switching Hart Revision

    1. Right click on the device and select Configure. 2. In the left navigation pane select Manual Setup and click on the HART tab. 3. Select the Change HART Revision button and follow the prompts. Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 50: Hardware Maintenance

    Do not remove the thermowell while in operation. Select any standard, off-the-shelf sensor for use with a Rosemount 248, or consult the factory for a replacement special sensor and transmitter combination.
  • Page 51 Reference Manual Operation and Maintenance 00809-0100-4825 May 2019 Table 4-2: Rosemount 248 Troubleshooting Chart (continued) Symptom Potential source Corrective action Loop Wiring • Check for dirty or defective terminals, interconnecting pins, or receptacles. Power Supply • Check the output voltage of the power supply at the transmitter terminals.
  • Page 52 The day portion of the date is invalid. Illegal month The month portion of the date is invalid. Illegal year The year portion of the date is invalid. Incomplete exponent The exponent of a scientific notation floating point variable is incomplete. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 53 Prompts user to press SAVE softkey to initiate a device-to-memory configuration memory transfer. Saving data to configuration Data is being transferred from a device to configuration memory. memory. Sending data to device. Data is being transferred from configuration memory to a device. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 54 <variable label> has an A variable related to this variable has been edited. Send related unknown value. Unit must be variable to the device before editing this variable. sent before editing, or invalid data will be sent. Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 55: Safety Instrumented Systems (Sis) Requirements

    All Rosemount 248 HART Transmitters must be indentified as safety certified before installing into SIS systems. To identify a safety certified Rosemount 248 Transmitter, make sure the device satisfies the requirements below: 1. Verify the transmitter was ordered with transmitter type option code "H" and option code "QT".

  • Page 56: Configuration

    4. Use the HART communicator to view detailed device status to ensure no alarms or warnings are present in the transmitter. 5. Perform reasonability check on the sensor value(s) versus an independent estimate (i.e. from direct monitoring of BPCS value) to show current reading is good. Rosemount 248 Temperature Transmitter Reference Manual...
  • Page 57 (i.e. from direct monitoring of BPCS value) to show current reading is acceptable. 8. Restore loop to full operation. 9. Remove the bypass from the safety PLC or otherwise restore to normal operation. 5.5.5 Inspection Visual inspection Not required. Special tools Not required. Rosemount 248 Temperature Transmitter Reference Manual...

  • Page 58: Specifications

    All failures detected by the transmitter diagnositcs or by the proof-test must be reported. Feedback can be submitted electronically at Emerson.com Specifications The Rosemount 248 Transmitter must be operated according to the functional and performance specifications provided in the Rosemount 248 Product Data Sheet 5.6.1...

  • Page 59: Appendix A Reference Data

    3. Click Manuals & Guides. 4. Select the appropriate Quick Start Guide. Ordering Information, Specifications, and Drawings To view current Rosemount 248 Ordering Information, Specifications, and Drawings, follow these steps: Procedure 1. Go to Emerson.com/Rosemount/Rosemount-248. 2. Scroll as needed to the green menu bar and click Documents & Drawings.
  • Page 60 Linkedin.com/company/Emerson-Automation-Solutions © 2019 Emerson. All rights reserved. Twitter.com/Rosemount_News Emerson Terms and Conditions of Sale are available upon request. The Emerson logo is a Facebook.com/Rosemount trademark and service mark of Emerson Electric Co. Rosemount is mark of one of the Youtube.com/user/RosemountMeasurement...

Table of Contents

Save PDF