The first engineer probably wanted to use an instrumentation amplifier in order to amplify and level shift the output of a "Bridge" load cell. This is not necessary with the ADC-24.
The ADC-24 is, in effect a single channel device with a multiplexer to give 16 single-ended or 8 differential channels. When you use more than one channel, each must be referred to the same analog ground reference. Each voltage measured must be within the common mode voltage range of the ADC-24 which is:-
Channel input to Analogue Ground (AG):- ±1.9 V (±39 mV to ±1250 mV ranges)
Channel input to Analogue Ground (AG):- ±3.0 V (±2500 mV range)
Analogue Ground (AG) to earth ground:- ±30 V
Please see page 11 of the manual:-http://www.picotech.com/document/pdf/adc20.en-3.pdf
I assume that your Load cell has a differential output and a required energisation voltage of 10V. The cell should have four terminals, a "+" & "-" energisation input and "+" & "-" signal outputs.
Connect the +10V power lead (from an external power supply) to the "+" energising input of the cell, connect the 0V lead to the "-" energising input of the cell.
Connect the "+" output of the cell to the Ch 1 input of the terminal board. Connect the "-" output of the cell to the Ch 2 input of the terminal board.
Connect the Analogue Ground (AG) connection of the ADC-24 terminal board to the "-" output of the cell, either at the cell or a channel 1 input of the terminal board. This is to give a stable analogue reference at the same voltage as the cell output.
When setting-up the channel on the ADC-24, choose "Differential input enable", +/-39mV range (or higher if necessary) and the sample rate required.
Your load cell will probably be rated for sensitivity in it's specification with a figure similar to "10mV/Volt at full scale". This means that for each volt of energisation applied, the differential output of the cell will give 10mV output at full scale load. In this case, 10V energisation will give 10 x 10mV = 100mV output at full scale. Depending on the exact output voltage of your Load Cell, you may want to increase or decrease the selected voltage range on the ADC-24 to suit. Use the most sensitive range that does not saturate on full load. Using the "Scaling" option, the correct engineering units can be displayed on the PicoLog screen and data file.
Please contact again if you still have difficulty.