Can the PM710 monitor positive or negative power and energy values?
The PM710 cannot distinguish whether the energy is going into or out of the load.
The PM710 is technically a 2-quadrant power meter.
Both power and energy in and out of the load are treated as additive. In other words "Absolute values" are represented. There is no differentiation between positive or negative power and energy values.
This applies to the all the RMS measurements:
Active power Total and per phase
Reactive power Total and per phase
Apparent power Total and per phase
Power factor Total
Unfortunately the PM710 does not provide the information in order to calculate this.
There is no register available to flag the direction of power or energy flow.