Temperature Control while in velocity

Hello Everyone,

I am using LAMMPS May 2016 version and want to control the temperature while pulling.

My system is 7 chains and the middle chain (group: Chain 1 ) being pulled. Each of the chains has many beads . I hole the ends (first and last beads) of the other chains (group: Ends_OtherNFCs) fixed in their positions, while the other beads of the surrounding chains are mobile. Pulling is applied by applying a linear velocity in the first bead (group: nfc_pull) of the middle chain (Chain1) in the -x direction.

I can control the temperature of the other chains (group: mobile_otherchains) by the temp/rescale. But my problem is I cannot control the temperature of the chain (output: temp2) which is being pulled. SO I am getting a lot of fluctuations.

The log file in the first step of the pulling looks like:

Step temp1 temp2 strex Press Volume PotEng KinEng E_bond E_angle E_dihed TotEng Pxx Pyy Pzz Lx Ly Lz
0 3.9551836 198544.45 -8.1267854e+09 2.0086199 1.3189955e+09 -562417.18 59764.531 26.41247 2.8004115 2.2189113 -502652.65 6.1536081 -0.013818537 -0.11392994 19892.382 266.42244 248.87756

DOes anyone have any feedback and advise me on how to control the temperature of the middle chain while it is being pulled?

THank you so much.

Part of the input file

fix 4 all nve

velocity Ends_OtherNFCs set 0 0 0 units box
fix 6 Ends_OtherNFCs setforce 0.0 0.0 0.0

fix 7 nfc_pull setforce 0.0 0.0 0.0
velocity nfc_pull set -0.001 0 0 sum yes
velocity Chain1_Remaining ramp vx 0.0 -0.001 x 200 20101 sum yes

fix 5 mobile_otherchains temp/rescale 200 5 5 0.02 1.0