OHAUS SD Series, Service Manual

CHAPTER 1  

GETTING STARTED

1.6 CALIBRATION 

For best results, calibrate the scale at regular intervals. Correct calibration weights must be 
available before starting calibration. (See Specification Table).  Multiple weights may be used to 
equal the required calibration weight. Calibration is unavailable in Dynamic Weighing Mode. 

CAUTION! 

BE CAREFUL HANDLING CALIBRATION WEIGHTS: THEY ARE VERY 
HEAVY.  IMPROPER LIFTING METHODS OR MISUSE OF CALIBRATION 
WEIGHTS MAY RESULT IN PERSONAL INJURY.   

1.  Allow time for the scale to stabilize after moving it from an area which is at a different 

temperature than the area where it is to be operated: one hour for each 5°F (2.7°C) 
change.  After temperature stabilization, allow an additional 20 minutes after turning the 
scale on, for the scale electronics to stabilize. 

2.  To select the weighing unit to be used, press 

UNITS

Cal

 until the correct unit is 

displayed, then press 

Yes

. 

Note

: Calibration can be stopped at any time: press 

UNITS 

Cal

or turn the scale off.  

3.  Press and hold 

UNITS 

Cal

until 

CAL

 is displayed. 

4.  With the platform empty, press 

ON/ZERO 

Off

to capture the scale 

zero. The display will show 

-C-

.  

5.  After the zero is captured, the required span calibration weight 

value in the selected unit appears.  

6.  Place the calibration weight on the platform and press 

ON/ZERO 

Off

. 

The display will again show 

-C-

.  

7.  After span capture, the display will return to the normal weighing 

mode.  

Note

: The message 

CAL E

 will appear if an incorrect calibration weight was applied.  

Repeat the procedure using the correct calibration weight.  

Calibration Locking

: By use of an internal switch, the calibration function may be locked 

(disabled), and unauthorized recalibration prevented.  

1.  With the scale powered off, remove the back housing section of the scale by unscrewing 

the four screws at the bottom.  

2.  Slide the switch on the PCB (marked 

SW3

) to the position marked 

CAL LOCK

.  

3.  Reassemble the housing.  

4.  If required, place tamper evident seals over the screw holes or the housing edges. 

If later recalibration is required, the housing will need to be reopened and the lock switch 
returned to the original position. 

Note

: When the lock switch is set to the 

CAL LOCK

 position, the power-on zero range is 

reduced to 10% of full capacity. 

SD Series Scales Service Manual

1-5

Ohaus Corporation  www.ohaus.com