What software? Arc, handling etc?
Try Setup-->Override Select and disable if you want to control via TP
Override may be executed in TP program.
and also in KAREL. Its common for programmers to hard code a speed for the application or to use some digital inputs on a group to set the speed. Its to prevent someone from accidentally slowing it down or forgetting to set the proper speed at reboot/restart.
Override can be set in TP program, can be set by external plc trough Group Input, max override can be set in variables $SCR_ColdOVRD, TPENBLEOVRD, ... So lots of things can cause this.
