Table 1 Field one is a value recored once every minute Fields include
"TimeStamp" and "pH Value".
Table 2 Field one is a value recorded upon a change in the value only.
Fields include "TimeStamp2" and 'pH Setpoint".

The Question: When I generate a line graph illustating the setpoint and the
pH Value over the one minute intervals the graph works perfectly.
I want to illustrate the setpoint change on the second horizontal graph line
at the time of change. If the setpoint is returned to its previous value the
setpoint plot line should look like a step in the line.
How do I ackomplish this?