Separate input from output
List the current input points and the output points on separate lines. For a 4–20 mA loop, copy the actual points from your maintenance sheet. If staff work in percent of span, include the current values assigned to zero and full scale.
Describe how the loop is powered
Tell us if the calibrator sources current or simulates a transmitter in an externally powered loop. Include any specified loop load or supply condition. Mention a voltage-input or loop-power function separately if you need it included in the work.
Stepped outputs and recorded values
If the procedure uses an automatic step or ramp, send its end points and timing and say which values the technician records. A steady output comparison and a review of the timed sequence have different requirements. Keep the original current points with any percentage-of-span values so there is one clear interpretation of the requested settings.
Include the instrument's previous certificate when continuing a calibration history. Mark any new range, mode or operating condition on the request. If a reading has become unstable, describe the observed behaviour and ask for assessment before calibration. Parts, adjustment and checks after any work need their own approval. RTS can confirm the available method and the source, simulation or measurement functions included in the quotation.
Current sources beyond the usual loop points
For a dedicated current source, identify AC or DC and write the actual current values in amperes or milliamperes. Include the selected output range, connection and load condition. A source feeding a resistance or test fixture has to operate within its available output voltage; tell RTS if the bench procedure specifies that condition. List any external amplifier separately. If the same instrument also measures current, give that input function its own point list.
CC-4643 separates current measure from current source work. Measuring the output of your DC source is matched to the measure entries, including separate permanent-facility ranges from 1 mA to 10 A on page 6. The much larger current figures in source entries are not evidence that every customer current-source output can be measured over the same range. For AC work, the listed current entries specify 50 Hz. Send the requested frequency even when the equipment has a wider rating. RTS can then agree the points and arrangement appropriate to the work you need, including whether it will take place at the laboratory or at your plant.
Identify a shared maintenance calibrator
Put the asset number and the technician who holds the leads on the request. If utilities and production share the unit, nominate one release contact. For work in several states, group the units by their return address.