As with any measurement, the quality of the result depends on the measurement instrument and the care with which the operator handles the measurement procedure. Many gages are designed to make this as easy as possible. A snap gage, for example, has the reference anvil, frame and measuring instrument built in. The same is true with a bench stand. To obtain a good measurement, all the operator really has to do is correctly apply the gage to the part.
对于任何测量，测量结果的质量取决于测量仪器和操作者处理测量过程的细心程度。许多计量器的设计都是为了让这一切变得尽可能简单。例如，卡规配备参考测量面、框架和测量装置。台式测量仪也是如此。要得到一次良好的测量，操作者真正需要做的就是正确地将量规应用到零件上。
With an electronic height gage, this is not quite the case. Electronic height gages are not as self-contained as other gages. They have the precision scale and the sensing probe, but no integral reference,which is the most critical part. Most electronic height gages are used on a granite surface plate, and the plate provides the reference for both the height gage and the part that is being measured. The quality of this base plate directly influences the measuring result. Thus, it is important to keep the plate free from dust, chips and dirt.
而当使用电子测高仪时，情况就不同了。电子测高仪不像其他仪器那样独立运行，它们有精确的光栅尺和传感探头，但没有内基准，这是最关键的部分。大多数的电子测高仪都是在大理石平板上使用的，该平板为测高仪和被测工件提供了参考平面。这种平板的质量直接影响测量结果。因此，保持平面没有灰尘、碎片和污垢是很重要的。
Most height gages are direct reading instruments that generally operate in ranges up to 36 inches. As such, they are especially susceptible to variations in temperature. Since the body heat of the operator (98.6 º F) is clearly above the room temperature (68 º F), any heat conveyed to elements of the measuring circuit (base plate, test piece, height measuring instrument, stylus) can cause local heat expansion and induce measurement errors. Operators should be very careful in observing the following rules:
大多数测高仪都是直接读数的，通常量程在36英寸的范围内。因此，它们特别容易受到温度变化的影响。因为操作者人体的温度(98.6ºF)明显高于室温(68ºF),任何热量对测量系统 (底座、工件、高度测量仪,测针) 的影响都可以引起局部热膨胀和测量误差。操作人员应非常小心遵守下列规则：
• Avoid touching the test piece with your bare hands directly before the measurement. Use gloves.
•在测量前避免徒手直接触摸测试件，应使用手套
• Do not touch other elements of the measuring circuit.
•不要接触测量系统的其他要素
• Only touch the height gage at points provided for this purpose: handles are usually provided to move the gage or engage the air bearings for positioning.
•仅触摸测高仪上允许接触的位置：手柄通常用于搬运或启动空浮进行定位。
• Avoid direct sunlight on the instrument, test piece, or base plate.
•避免阳光直接照射在仪器、测试件或底板上
• Do not set up the measuring station in proximity to radiators or in the path of air ducts.
•不要在靠近散热器或风口的地方放置测量台
• Do not check test pieces that were transported through very hot/cold rooms shortly before measurement.
•不要测量之前通过非常热/冷的房间运输的工件
• For high precision measurements, put the test piece on the base plate and let it adjust to ambient temperature (approx. ¼ to 8 hours,depending on the size of the part).
•对于高精度测量，将工件放在平板上,并让其等温(约15分钟~8小时，取决于工件的大小)
Once the measuring loop is verified,there are two other critical references that need to be established.The first is the zero-reference for the measuring system. With automated height gages, this is done automatically whenever the gage is turned on. In a manually driven gage, the gage must be zeroed on the granite plate before it can be used. With a motor driven unit, the gage will automatically move down to touch the surface to set its reference point. It’s not a badpractice to initiate this zeroing routine a second time, just to make sure that no dirt or other anomaly has introduced an incorrect reference. Since setting this reference is critical to all the measurements you will make, it is certainly worth the time and effort.
一旦测量回路得到验证，还需要确定另外两个关键因素。首先是测量系统的参考零位，使用自动测高仪时，只要打开仪器就会自动进行置零。在手动驱动的仪器中，仪器在使用前必须在大理石台面上置零。通过电机驱动单元，仪器会自动向下移动以接触表面并设置其参考零位。而之后再启动一次这个归零程序也并不是一个坏习惯，只是为了确保没有污垢或其他异常。由于设置此参考零位对于您将要进行的所有测量都非常重要，因此它确实值得您花费时间和精力。
The other important reference is the correction for probe ball diameter. If a height gage is to be used only for length measurements taken with the probe moving down, probe diameter is not important. The contact point of the probe will be the same as in zeroing. But, if grooves, diameters, or the hole locations are being measured,or if any measurements are taken with the probe moving upwards, the probe ball diameter must be known and taken into account.
另一个重要的要素是校准测头的球径。如果测高仪只用于测头向下测量高度，测头直径就不重要了。测头的接触点与归零时是一致的。但是，如果要测量凹槽、直径或孔的位置，或者测头向上触测时，则必须清楚并考虑测头的球径。
Ball diameter is specified for the probe, of course, but there is always some degree of variation. Actual ball diameter should be added to any dimension that is probed in the upward direction.
当然，测头的球径是指定的，但总是会有一定程度的变化。在向上触测的任何尺寸上都应该加上实际的球径。
On height gages that have even the most basic electronic control, this dimension can be measured as part of a set-up routine and is automatically included in all measurements. The automated process uses a fixture provided with the gage, or the test can be simulated with a couple of gage blocks. The fixture sets up a plane that is measured by the gage from both directions. The gage then looks at the difference between the two measurements and calculates this as the ball diameter.
通过测高仪上基本的程序控制，这个尺寸的确定将作为设置程序的一部分来进行，并自动应用到之后所有的测量中。自动校准过程中会使用带有量块的夹具，或者可以用两个量规块进行模拟。夹具提供了一个可以从两个方向测量的平面，然后观察两个测量值之间的差值，并将其计算出测球的直径。
Failing to recheck for ball diameter can be a deadly pit fall when a probe tip is changed. Going from a 10 to a 5mm ball tip would be disastrous if not recalculated.
如果没有重新校准测头直径，而此时球径恰恰改变了，这将会是一个致命的陷阱。对于一个球径10到5毫米的测头来说，如果没有重新校准测头直径的话结果将非常糟糕。
文章摘抄自马尔公众号
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