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ADS1232REF: Question on blue terminal block and PIns next to the terminal block

Part Number: ADS1232REF

Bob,  We have been using the blue terminal block to attach a 4 wire load cell for years.  Could we use the pins on the connecting block immediately next to the Terminal block, and get equivalent results.  Am I correct in thinking that the blue terminal block location (+5VA, N1-,  N1+, and GND)  are equivalent to the PINs on the PIN block (EXC+, SG-, SG+, and EXCSNS-) .

  • Hi Kurt,

    The screw terminal blocks are nearly identical to the header except AIN2 is not available, the signal order is slightly different, and the EXC- connects to AGND through a switch U7 to break the excitation.  See Table 7 on page 21 and explanation in section 6.4.2 of the ADS1232REF user's guide.  You can also view the routing in Figure 10 on page 25 and compare schematically in Figure 11 on page 26 for connectors for J4, J5 and J6.

    Best regards,

    Bob B

  • Thank you - you almost resolved my issue - but now I have another question:  I do understand the AIN2 is not available with the PINS and that the order of the pins is slightly different than the order on the screw terminal block.  But I am unsure of the implication of EXC- connecting to AGND through a Switch.  I think this is the switch on the board that can be either be set as +5V or EXT.   We normally set this switch to +5V.   I don't know the meaning of "the EXC- connects to AGND through a Switch U7 to break the excitation".  We would want excitation continually.  Does this mean that switch has to be a certain position to cause Excitation ? 

    I am desiring things the be the same as if I were using the Terminal Block connectors:  +5VA, N1-,  N1+, and GND

  • Hi Kurt,

    The low-side switch is not the kind of switch that you can manually flip.  You are referring to SW7, and the switch I am talking about resides on the bottom of the PCB as U7 part number TS5A3166DCK, which is a semiconductor analog switch that is controlled by a GPIO on the microprocessor.  The switch is normally open when the control input is low (at 0V).  The switch connects to GND when the input to the control pin is high (3.3V).  Fortunately the default operation for U7 is to close the switch to ground by the GPIO pin output as high.

    You should be ok to use the ADS1232REF in the desired  operation.  However, if you have concerns another possible option would be to remove U7 from the board and solder a short jumper wire from the EXC- to the ground lug on the bottom-side of the ADS1232REF.  I have demonstrated this below.

    Best regards,

    Bob B