Measuring ambient temperatures is a common application with a number of solutions depending upon your use of the word “ambient”.
Low Cost Solution
If you simply need to monitor the temperature inside an enclosure, the simplest and least expensive choice is the T2X DWB wall mount assembly. It consists of a loop-powered transmitter with a 1000 ohm RTD incorporated into a wall-mounted box.
If you want to mount the temperature transmitter on the back panel, you can use this model (pictured at left):
Model T2X / PT10 / 4-20MA / 8-42DC [DWB]
If you want to mount the T2X DWB temperature transmitter on DIN rail use this one:
Model T2X / PT10 / 4-20MA / 8-42DC [DWBDN]
More Conventional Transmitter Solutions
The low cost solution is not for everyone, however. For example, your application may require HART protocol or a local display or both. For these more sophisticated applications, you can use transmitters with more advanced capabilities by mounting them on a DIN-rail in the area in which you wish to measure the ambient temperature, but without a sensor.
Configure the transmitter for a Type T or Type E thermocouple and put a copper short on the thermocouple input terminals. The temperature transmitter will then read the RJC (Reference Junction Compensation) temperature. You can also add a -40°F to 185°F temperature scale on the 4-20mA signal. This scale matches the ambient operating temperature specification for Moore Industries transmitters. Because of the accuracy of our RJC temperature sensor and its placement, this simple approach will yield tracking of the enclosure temperature within ±0.5°C.
For example: Specify a DIN-rail mounted THZ3, Model #: THZ3 / PRG / 4-20MA / 12-42DC [DIN] (pictured at left). Or you can use a TDZ3 hockey-puck with display to read temperatures at the location, Model# TDZ3 / PRG / 4-20MA / 12-42DC [DN] (pictured at right)
Be sure to include a USB Configuration cable with each of these. Part Number 804-030-26.
Ambient Outdoor Temperatures
If you need to measure ambient temperatures outdoors, you will need to protect the temperature transmitter from the elements. You also may want additional physical protection for the sensor and the WORM Nose provides that protection, yet yields good response time. Use one of these assemblies, which are more like traditional process configurations.
Here are some examples:
Model T2X / CL6 / D25 / S316 / -WSPT14 –NPL -WN [LH2NSP]
Model THZ3 / CL6 / D25 / S316 / -WSPT14 –NPL -WN [LH2NSP]
Model TDY / CL6 / D25 / S316 / -WSPT14 –NPL -WN [BH2NGP]
Model TDZ3 / CL6 / D25 / S316 / -WSPT14 –NPL -WN [BH2NGP]
You can use a USB Configuration cable for programming each of these: Part Number 804-030-26. Or, with the HART transmitters, you can program them with a HART modem or HART handheld device.
Get a handy reference on temperature measurement technology and techniques by requesting your own copy of Moore Industries' Temperature Reference Guide.
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