upper limiting value meaning in English

上极限值

In selecting the upper limit value , sufficient room shall be maintained
在选择压力表的上限值时应留有充分的余地。
Generally , under the situation of steady tested pressure , the maximum working pressure shall not exceed 2 / 3 of the upper limit value of the instrument ; while in measuring pulse pressures , the maximum working pressure shall not exceed 1 / 2 of the upper limit value of the instrument ; and while in measuring high pressures , the maximum working pressure shall not exceed 1 / 3 of the upper limit value of the instrument
一般在被测压力稳定的情况下，最大工作压力不应超过仪表上限值的2 / 3 ；测量脉动压力时，最大工作压力不应超过仪表上限的1 / 2 ；测量高压时，最大工作压力不应超过仪表上限的1 / 3 。