When the use of the HT-5500 Handheld Digital Tachometer

 

During the measurement of 354 r/min
Error count 354 x ± 0.02 % ± 1=± 1.0708
When the display value is unit of 1 r/min, the accuracy is ± 1 r/min.

During the measurement of 8.8 r/min
Error count 88 ｘ ±0.02 % ±1=± 1.0176
When the display value is unit of 0.1 r/min, the accuracy is ± 0.1 r/min.

When the use of the TM-3100 series Digital Tachometer

 

During the measurement of 354 r/min Error count 354 x ±0.01 % ± 1=± 1.0354 When the display value is unit of 1 r/min. the accuracy is ± 1 r/min

 

During the measurement of 8.8 r/min
Error count 88 ｘ ±0.01 % ±1=± 1.0088
When the display value is unit of 0.1 r/min, the accuracy is ± 0.1 r/min

 

Incidentally,
During the measurement of 8.80 r/min
Error count 880 ｘ ±0.01 % ± 1 = ± 1.088
When the display value is unit of 0.01 r/min, the accuracy is ± 0.01 r/min.