CEMB USA T-NC_30-S User Manual

Page 4

TRANSDUCER POSITIONING

Refer to drawing Nr. 19457

Drill holes on the machinery for the sensor support and for any cable protection

devices (sheaths, ducts etc.).

2) Drill a hole to fasten the converter box at a distance from the machinery shorter

than that of the connecting cable (5m).

3) Separate the sensor from the converter by disconnecting the cable from the terminal

board inside the converter (carefully note the polarity of the two leads making up

the cable), then mount the sensor on the support prepared in point 1

4) After checking that the machinery lies in position K (ZERO position with the

machine stationary), perform a preliminary mechanical adjustment of the GAP by

acting on the nut-lock nut device of the sensor. The GAP indicated in the

application drawing refers to the mid point of the measuring range of the

transducer. In the case of frontal measurement of the displacement, the mid point of

the measurement range of the sensor corresponds also to the mid point of the

measurement to be made. If the measurement is longitudinal (sliding of an inclined

block) instead of frontal, proceed to calculate the GAP corresponding to the

position K of the machinery, taking due consideration of the measuring range and

angle of inclination of the block.

5) Fasten the converter box using the holes drilled in point 2 and attach any

protective sheaths if necessary. Reconnect the sensor cable to the converter

terminal board making sure of the exact polarity of the leads making up the cable.

6) Proceed to the electrical connection of the converter with the measuring

instrument.

The following instructions refer to the machinery under the supply, which requires

longitudinal measurement (inclined block) of the expansion, according to the data

given in the above-mentioned table attached to this section; otherwise adapt the

data to the plant characteristics.

With the machine in position K and with the measuring instrument operating, use

the nut-lock nut device of the sensor to search for the exact coincidence between

the mechanical gap and the electrical calibration of the converter in one or,

better, both of the following ways:

- reading on a voltmeter connected across pins A and D of the converter connector

(or else across the terminals corresponding to the transducer signal input on

the terminal board of the instrument) on the scale 0 to 10 Vdc of the range of

measurement (0Vdc= scale start, 10Vdc=full scale) of the volts corresponding

to the Gap; as the Gap indicated in the application drawing of the transducers

refers to the mid point of the range of measurement, under this condition there

should be a corresponding reading of 5 Vdc.

Hence the sensor position should be adjusted through small displacements along its

longitudinal axis until the value of 5 Vdc on the voltmeter.

8) Then lock the sensor in position using the nut-lock nut device.

9) Close the converter making sure that it is spray- and dust-proof.

REMARKS REGARDING CORRECT POSITIONING OF TRANSDUCERS T-NC/S

1) Never, under any circumstances, modify the sensor / converter cable length: this

would cause a measuring error.

2) The end part of the sensor must lie at a distance from metal materials different

from the one involved in measuring the distance: at least twice the max. amplitude

of measurement (see application drawing).

3) When mounting the sensor, a reference cone should be prepared at 90° vertex from

the sensor tip. No metallic material must be introduced in the cone apart from the

surface to be measured.

UTS051024

ASTD58120