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Process Calibration Tools Frequently Asked Questions


Q: Just what can you do with HART smart devices with the Fluke-744?
A: The Fluke 744 can perform calibration on many HART devices and download the results for storage. The 744 can program a variety of attributes in a transmitter but not all . It will not replace a HART communicator for all hart devices to perform all HART tasks. It will not store the configuration of the transmitter to upload to a computer. It will capture the devices performance via a performance test and will capture the transmitter tag number, serial number and ranging.

The 744 can program the tag number, measurement units, range, dampening and transfer functions. It can adjust most if not all mA outputs of transmitters, command a transmitter to perform a loop test and perform the pressure zero adjustment of pressure transmitters as these are universal commands.

For the devices we support we can perform sensor trim on the inputs of temperature and pressure transmitters and configure the sensor type for temperature transmitters. For supported multivariable transmitters we can map the variable and configure the dual sensor configuration (setting a dual input temperature for hot back up for example).

The 744 can do light programming and configuration and is intended to replace the need to carry a communicator to the field for calibration. Some users find its’ capabilities eliminate the need to take a communicator to the field except for non-supported devices such as valves or other complicated devices that require a laptop or communicator.

The HART calibration application note has the HART “tree” of available commands, list of supported devices and example of how to use the 744 to calibrate both a HART temperature and pressure transmitter. This application note( lit# 1262439) is available for download from the Fluke web.

Q: What are some of the costs and challenges of moving from a paper-based instrument calibration system to digital record keeping?
A: Often acquisition costs are the smallest challenge in setting up digital record keeping. Documenting Process Calibrators (DPC's) being multifunction devices are the premium priced field calibrators ranging from $5K-10K. That said, they are usually multifunction giving them a wide workload coverage and they often have other useful features such as HART configuration capabilities or the ability to log measurements for trending. Even if the documenting aspect of these calibrators is not used, these DPC's replace the need for a bucket full of tools. Calibration Management Software (CMS) pricing varies greatly. Single user entry level products range from $2K, but more comprehensive networked versions with sophisticated predictive maintenance capabilities and workload management can cost as much as $100K or more. The more of the software you use, the better value on your return.

The critical element to succeeding in setting a digital record keeping system goes beyond the decision to commit funds to a purchase. The purchase needs to be accompanied by an additional commitment from maintenance management to staff if it is to succeed. Up front, this means assigning a super user that is the key operator/administrator of the system. There is a lot of initial work getting all of the instrument tags into the CMS.

This can often be done via ASCII import of the existing tag information if there are any kind of electronic records that describe them. Critical information includes (but not limited to) tag number, serial number, input span, required accuracy, and test procedures. Once the initial information is entered, there is follow on maintenance refining the tag information, adding new tags, and maintaining test equipment record for traceability purposes.

Q: What are the advantages of calibration management software over paper- bases systems?
A:While the challenges and costs seem daunting, the reward, once a DPC/CMS system is in play is huge. It is easier to predict staffing requirements over periods of time. Doing predictive maintenance of critical tags is enabled through advanced analysis tools such as drift plot analysis. These tools allow the system owner to use As-Found calibration data to do calibration interval adjustments or determine if the maintenance cost of a device is such that its' replacement is justified.

In the event of an audit by a quality organization or regulatory agency, access to critical calibration records for suspect instruments is at the fingertips of the process owner. No concerns of legibility or finding a specific piece of paper. Most CMS packages have flexible search tools for finding tags sorted in a variety of ways. For example, find all the pressure instrument tags in a process unit to send a technician out to perform calibrations.

One of the main benefits is the interaction of the procedures loaded into the DPC from the CMS software. Once the procedure for an instrument is loaded into the DPC, the user selects the pre-configured procedure for the tag. Many DPC's can give the user connection information or walk the technician through an isolation procedure or lock-out/tag-out procedure. Once connected, the DPC will be automatically preconfigured correctly for test. The inputs to the tag are known, the expected measured output is known as the expected tolerance. With that information, the DPC can determine pass/fail while logging the As-Found calibration results. In the event of a failure, many DPC's can guid the user through the adjustment process. Once adjustment is completed, the calibration performance test can be repeated and the As-Left calibration results are recorded. This information is recorded into the DPC memory for alter upload into the CMS, after which the results can be reviewed and/or printed. There are no issues with legibility of test records or transcription errors. Results cannot be falsified and the DPC's can be reviewed prior to upload to ensure that the procedures downloaded from the CMS were used. With a system such as this, the integrity of the data is both insured and protected.

Q: How do I change the mA range on my Fluke Process Calibrator/Meter to 0-20mA or 4-20mA?
A:Fluke 705 - Press and hold the up arrow button (?) on power up until the new mA zero value appears on the display. Repeat to change back.

Fluke 707 & 707Ex - Press the “MODE” button on power up, you can release the buttons after unit powers up.

Fluke 715 – Select the “Output” zero value and press and hold both up arrow buttons simultaneously (??) to store and repeat for the span value.

Fluke 787 – Press and hold the “RANGE” button on power up.

Fluke 789 – Press and hold the “RANGE” button on power up.

Fluke 725, 725Ex, 726 – In the Output mode select the desired zero value and press and hold the “0%” button for ~3 seconds. To set the span, select the desired value and press and hold the “100%” button for ~3 seconds.

Fluke 772 & 773 – Press the shift button to activate ?, ?, ?, and ? to adjust the source output. Long press the 0% or 100% button until the percent value changes to either 0.0% for zero or 100.0% for span.

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