This value is the hysteresis margin applied to channel 1's alarm thresholds, preventing the alarm from rapidly flapping on and off when the temperature hovers near a limit. An admin tunes this so a temperature bouncing right at ch1LimHi or ch1LimLo doesn't generate a flood of alarm transitions, only clearing the alarm once the reading moves back past the limit by this margin. For example, a hysteresis of "1.0" on a high limit of 30 would mean the alarm doesn't clear until the temperature drops back below 29 degrees.