I recently ordered two of the PR33-36 (0-20 VDC) units, and got two units labeled “PR33-13 0-10V ADC” in silkscreen on the top of the card, and with a paper label reading “0-20 VDC” on the bottom.
I connected the unit to two voltage sources, 13.6 and 12 VDC, and got maximum readings for both channels.
Lowering the one of voltages to the 9-10 VDC range yielded readings on that channel less than the maximum that were linearly related to one another, as one would expect.
Input voltage to the board is 12 VDC
The sampling software configured the MCP3428 to continuous conversion mode with gain=1 and 12-bit resolution.
Did I get sent the wrong parts, or is there some way to get voltage readings above about 10 VDC?