Fluke HART SCIENTIFIC 1502A Manuel d'utilisateur télécharger pdf (Page 41)

10 Troubleshooting

In case you run into difficulty while operating the 1502A, this section provides

some suggestions that may help you solve the problem. Below are several situa

tions that may arise followed by possible causes of the problem and suggested

actions you might take.

Incorrect Temperature Reading

While attempting to measure temperature the display shows an incorrect value.

If the temperature readings seem to be incorrect you should first check to see if

the resistance is being measured correctly. Select ohms to display resistance. If

the resistance is incorrect refer to the next subsection for troubleshooting incor

rect resistance readings. If the resistance is being measured correctly but the

displayed temperature value is incorrect consider the following possibilities.

•

One or more coefficients are incorrect. This is a common mistake.

While entering coefficients it is easy to miss a digit or sign. Check all the

values carefully comparing them with the values on the calibration certifi-

cate for the probe.

• The selected conversion type is incorrect. Check to make sure the cor-

rect conversion type (ITS-90, RTD, or IPTS-68) is selected.

• The measurement is out of range. The 1502A may not be able to calcu-

late temperature accurately if the resistance is outside the valid range. The

measured resistance may be too low or too high if the actual temperature

is too low or too high or if there is a problem with the sensor (see below).

Incorrect Resistance Reading

While attempting to measure resistance the display shows an incorrect value.

Consider the following possibilities.

•

Poor or incorrect connection of the probe. A common mistake is to

connect the wires of the probe to the wrong terminals. Check the wiring

carefully (see Figure 1 on page 12).

•

Open, shorted, or damaged sensor or lead wires. Check the resistance

across the sensor using a hand-held DMM. Also check the resistance be

tween common pairs of leads. Check to make sure there is no conductiv

ity between any of the leads and the probe sheath. Use a good-quality

sensor to avoid errors caused by drift, hysteresis, or insulation leakage.

•

Electrical interference. Intense radio-frequency radiation near the 1502A

or the probe can induce noise into the measurement circuits resulting in

erratic readings. The 1502A is intended to operate in a laboratory environ

ment with limited radio-frequency noise. If interference seems to be a

problem you might try eliminating the source of interference or moving

the 1502A to a different location. A well-grounded, shielded cable should

be used for the probe leads.

10 Troubleshooting

1 2 ... 36 37 38 39 40 41 42 43

Commentaires sur ces manuels

Pas de commentaire

Fluke HART SCIENTIFIC 1502A Manuel d'utilisateur Page 41

Commentaires sur ces manuels

Produits connexes et manuels pour Thermomètres Fluke HART SCIENTIFIC 1502A