Thermo Scientific Micro-Tech 9101 - Page 98

Maintenance and Troubleshooting
Load-Cell Problems
4-4 Micro-Tech 9101/9201 Reference Manual, Rev J Thermo Fisher Scientific
The troubleshooting procedures detailed below consists of four simple
checks, as follows.
 Verify excitation/sense voltages.
 Verify proper sense jumper settings.
 Verify load cell mV signal at the Micro-Tech is within range.
 Verify load cell mV signal at the junction box is within range.
The Micro-Tech has a Diagnostics menu to help you troubleshoot the
load cells. Go to “Main Menu 3—Diagnostics.” Two menus pertain to
load-cell troubleshooting, as follows.
 A/D Gross and A/D Net (Diagnostic Scroll 1)
 Weight on Load Cell (Diagnostic Scroll 2)
This is a digital representation of the mV signal coming from the
load cell. The Micro-Tech maximum A/D is equal to 103,009 at 30
mV. Weight at the load cell can be calculated using either A/D
counts or mV input. Refer to the figure below.
measured DC mV
* Total load cell capacity = Weight at the load cell
exc. Volts * LC mV/V
3 mV/V
A/D Gross
* Total load cell capacity = Weight at the load cell
103009
2 mV/V
A/D Gross
* Total load cell capacity = Weight at the load cell
68673
1.8 mV/V
A/D Gross
* Total load cell capacity = Weight at the load cell
61806