DayTronic 5M78 Manuel - Page 10

Parcourez en ligne ou téléchargez le pdf Manuel pour {nom_de_la_catégorie} DayTronic 5M78. DayTronic 5M78 16 pages. Ac strain gage conditioner module

Imprimer la page

3. CALIBRATION

With the transducer loaded as in step (f), adjust the Symmetry control (right

(j)

above the PHASE control adjustment) to obtain a dead weight reading equal to

that obtained in step (f).

(k)

If dead weight calibration is not practical and the transducer manufac-

turer has supplied a calibration resistor (or resistor value), install the

recommended calibration resistor. See Fig. 5

(l)

Perfom steps (b) thru (e). Now activate the SHUNT POSITIVE (SHP) terminal

and adjust the SPAN controls until the instrument output is equal to the Equivalent

Input value simulated by the installed resistor. Shunt is performed at zero load.

(m)

If a negative Equivalent Input value is also provided on the calibration sheet

of the transducer under calibration, activate the SHUNT NEGATIVE (SHN) terminal.

Confirm that the negative value can also be obtained. If necessary, adust the SYMMETRY

control to obtain the negative Equivalent Input value as listed on the calibration

document. The SYMMETRY control has approximately 7% authority, full scale.

If dead weight calibration is not practical and the transducer calibration

data is unknown, the Equivalent Input value for the factory-installed

calibration resistor can be approximated

mv/v sensitivity rating of the transducer

known.

where

Sample Calculation: Assume that K = 3.000 mV/V for a 5000-pound loadcell

(fullscale) with a bridge resistance of 350 ohms.

Note: Above calculation is useful in applications involving non - star bridge shunt calibration strain gage

bridges (for example DC bridges, and slip ring type torque sensors). Rotary transformer type sensors

which use star bridge shunt circuit will not equate properly and the sensor's published calibration

data should be referenced.

Calibration 5M78.3

(cont.)

25000 R

X =

K R

X =

Equivalent Input, % of full scale

bridge resistance, ohms

K =

transducer sensitivity, mV/V full scale

calibration resistance, ohms (59 k installed)

25000 x 350

X =

59000 x 3

as follows, assuming that

and the bridge resistance

49.4%

of full scale = 2472 pounds

the

are