Measurements For Fault Localisation; Power Supply; Load Cell; Testing Load Cells With A Multimeter - Seca 334 LC Service Manual

Measurements for Fault Localisation

4 Measurements for Fault Localisation
The following section contains an overview of measurements that can be made for
specific fault localisation.
4.1

Power supply

Measurement of the power supply to the PCB indicates whether the leads from the
battery compartment and/or power pack are defective. A multimeter is used for
measurement at the measuring points B (see Appendix
4.2

Load cell

The most effective method for establishing a defect in the load cell is to use the seca
serva diagnostic function. If this is not available, another option is to use a multimeter.
Measurement with a multimeter is however not as conclusive, so this method should
always be second choice here.

4.2.1 Testing load cells with a multimeter

The load cell is first unsoldered from the electronics and the ohmic resistance between
the different connecting wires measured using a multimeter. The following tables show
the values to be expected for the various load cells:
Measurement between
V and Sig
+
V and Sig
+
V and Sig
-
V and Sig
-
Sig /Sig-/V
+
[334|335|382|383|384|385|833|834|835|874|875|876|877|878|769|799|780|869|899]
03.04.2013/JEG
(green and red)
-
(green and white)
+
(black and red)
-
(black and white)
+
/V- and aluminum body
+
of load cell
Table 6: Load cell resistances
19 (24)
)
.
Ohmic resistance [Ω]
~ 800-850
~ 800-850
~ 800-850
~ 800-850
> 500 M
seca
30-34-00-864