FLIRs PTUs utilize a worm drive which is designed to have very high step resolution and very low backlash in factory-new condition. However, backlash can develop over time due to gear wear. FLIR does not have a backlash specification, since the rate and amount of gear wear varies with the application, type of load, acceleration settings, and many other factors.
If a unit has been heavily loaded, has a high duty cycle, or is used at high speeds or acceleration settings, backlash may become a concern.
In certain applications, payload offsets, counterweights, etc., may be designed which use gravity or spring force to preload gears and reduce the effects of backlash.