Percent of a change, not percent of a Celsius reading
WIKA's response-time guidance describes a temperature step and percentage response values. In an RFQ, define the initial and final temperatures so that t50 and t90 identify elapsed time to 50% and 90% of that change. Compare values only with their stated test conditions; a water test is not automatically an air-service result. The primary reference is linked below.
The threshold calculation is T_initial + f × (T_final − T_initial), where f is 0.50 for t50 or 0.90 for t90. The following numbers are original teaching examples, not a test standard, a process recipe or WESIVO performance data. No response time in seconds is claimed.
Heating example: 20°C to 80°C
The change is 60°C. The t50 threshold is 20 + 0.50 × 60 = 50°C. The t90 threshold is 20 + 0.90 × 60 = 74°C. Record the elapsed time from the agreed step origin to the applicable threshold using the agreed output and test procedure. Taking 90% of the final Celsius reading would give 72°C; that is not the 90% step threshold in this example.
Cooling example: 80°C to 20°C
The change is −60°C. The t50 threshold is 50°C and the t90 threshold is 26°C. The same fractional-change rule works for cooling. State whether the supplier's evidence covers heating, cooling or both rather than assuming that one recorded trace establishes every operating direction.
Do not infer a t90 guarantee from a t50 value without an agreed and justified dynamic model. This guide does not assume that an installed assembly behaves as an ideal first-order system.
Make the compared configurations identifiable
WIKA's thermowell article explains that a well introduces an additional thermal path and that material and dimensions influence response. Therefore, label the submitted configuration. Keep the specified protection and mechanical suitability in the design review; a bare-probe curve is not automatically evidence for an assembled instrument.
The following is a proposed procurement record, not a substitute for an applicable test standard:
- Identification: tag, model configuration, serial number where available, drawing and revision.
- Thermal input: medium, flow condition, initial temperature, final temperature, direction and method of creating the step.
- Mechanical setup: immersion, probe geometry, insert fit and thermowell configuration.
- Recording: reference instrument, measurement point, time origin, acquisition interval and the original time trace.
- Output settings: transmitter range, damping, input filtering and any software processing included in the reported result.
- Acceptance: required percentage, maximum permitted elapsed time if specified by the project, decision rule, date and reviewer.
Keep three different questions separate
Accuracy asks how close a reading is to its reference under defined conditions. Thermal response asks how the assembly follows a temperature change. An electrical-loop check asks what the downstream equipment does with an applied signal. Request a separate record for each required activity.
An RTD resistance simulator does not heat the installed sensing element. Likewise, a transmitter output update interval is not a measured thermal response time. If the purchasing requirement concerns the value recorded in a PLC or historian, agree on the complete measurement boundary and settings with the integrator; do not label a sensor-only trace as that system result.
What to send WESIVO
Use the linked TT30E or TT20R product enquiry route and temperature catalogue to begin configuration discussion. Send the installation drawing, process conditions, required output and the response-test requirement. Ask which exact configuration and test evidence can be offered. This article supplies general technical interpretation; it does not establish a t50/t90 specification, certification or process qualification for any WESIVO product.
百分比针对温度变化量
WIKA 的响应时间说明介绍了温差阶跃和百分比响应值。询价时应给出初始与最终温度，使 t50、t90 分别表示达到此次变化量 50%、90% 所需的时间。比较时必须保留测试条件，水中测试不能自动代表空气工况。原始技术资料见下方链接。
门限计算为：初始温度 + f ×（最终温度 − 初始温度），其中 t50 对应 f=0.50，t90 对应 f=0.90。以下为原创教学算例，不是试验标准、工艺配方或 WESIVO 性能数据，也没有声称任何秒数的响应指标。
升温算例：20°C 到 80°C
变化量为 60°C。t50 门限为 20 + 0.50 × 60 = 50°C；t90 门限为 20 + 0.90 × 60 = 74°C。按约定的输出与测试程序，从约定的阶跃起点记录达到相应门限的时间。若直接取最终摄氏读数的 90%，会得到 72°C，这并不是本例的 90% 阶跃门限。
降温算例：80°C 到 20°C
变化量为 −60°C。t50 门限为 50°C，t90 门限为 26°C。降温同样按变化量比例计算。应注明供货方的证据覆盖升温、降温还是二者，不能把一次曲线视为证明所有运行方向。
没有约定且合理的动态模型时，不应根据 t50 推定 t90 保证值。本文不假设安装总成必然符合理想一阶系统。
明确比较的是哪一种配置
WIKA 的套管文章说明，套管增加传热路径，其材料及尺寸影响响应。因此，应标明提交曲线对应的配置，并保留设计所需的保护及机械适用性核对。裸探头曲线不能自动作为完整仪表总成的证明。
以下为建议的采购记录项目，不能替代适用的试验标准：
- 身份信息：位号、型号配置、可提供的序列号、图号及版本。
- 热输入：介质、流动条件、初始温度、最终温度、变化方向及阶跃实现方法。
- 机械安装：浸入深度、探头结构、芯体配合及保护套管配置。
- 数据记录：参考仪表、测量点、计时起点、采集间隔及原始时间曲线。
- 输出设置：变送器量程、阻尼、输入滤波，以及结果所包含的软件处理。
- 验收约定：响应百分比、项目规定的最大允许时间（如有）、判定规则、日期和审核人员。
分开回答三个问题
准确度关注规定条件下读数与参考值的接近程度；热响应关注总成如何跟随温度变化；电气回路检查关注下游设备如何处理施加的信号。需要哪项活动，就分别索取相应记录。
热电阻电阻模拟器不会加热实际安装的感温元件。变送器输出更新间隔也不是实测热响应时间。若采购要求针对 PLC 或历史数据库记录值，应与集成方约定完整测量边界及设置，不能把仅测传感器的曲线标注为整套系统结果。
向 WESIVO 提交什么
可通过下方 TT30E、TT20R 产品及温度样册入口讨论配置。请提供安装图、工况、所需输出及响应测试要求，确认能提供的具体配置和证据。本文提供通用技术解释，不构成任何 WESIVO 产品的 t50/t90 指标、认证或工艺资格承诺。
Discuss your application
Send your medium, operating conditions, connection, output, quantity and destination. WESIVO will review the configuration before quotation.