Change IR-DROP constraint (70% of VDD) in Tempus

Hello,

I'm usingTempus (v. 15.14)  to perform time analysis using IR-DROP (from Voltus).

I read the IR-DROP file (.iv) using: "read_instance_voltage -min -ir_drop myfile.iv" (OK)

However, when I perform "report_timing", I got an warning:

**WARN: (IMPESI-2012):    The instance U3_INST_next_reg_5_ has an IR drop voltage(0.68122V) which is less than 70% of nominal vdd(1V). Ignoring IR drop for this instance and using 70% of nominal voltage vdd(1V) from the IR drop file which is 0.7V as voltage.

My question: Is there a way to change this constraint of 70% of VDD? I work with radiation and I would like to see the effects for bigger IR-DROPS.

Thank you in advance,

Raphael