Updated 7th June 2022


Q. What is the Scope of Supply for LTB Sensor?

A. Sensor, Operator's manual (On data carrier), Quick Start Guide and PC software (On data carrier).

     No Mounting Nut, No Fixed Bracket, No USB Cable, and No USB Communication option.


Q. How to set Emissivity in LTB Sensor?

A. The LTB sensor does not have a USB Communication option so the only left option for setting Emissivity is using a Rotary Switch.


Q. Does any version offer a 0-5V output?

A. No, the mV output is 0-10V. For a 0-5V, choose 0-20mA output (6 and 12-wire versions only) and use a 250 ohm resistor.


Q. Can the device analog output ranges be scaled to my requirements?

A. Yes, for the mA and mV output, scaling is possible. We have an example of how to make this change using the DTMD software click for article


Q. The T4.0 LTD version is effectively a replacement for applications covered by the DZA TX. Is it supplied (like the DZA) with air purge and water cooling?

A. Special Air purge only. The water cooling accessory must be ordered separately. The water jacket from the DZA TX is not useable for the T4.0 as it was a factory fitted build option. Additional information can be found in the manual Rev 2.4 section 5.9.1 page 54.


Q. What are important use considerations when replacing TX sensors with Thermalert T4.0?

A. The main consideration is the behaviour of the mA output. When the sensor is underange the mA output will drop to 3.5mA (TX was 3.99mA). With some control systems (not all), this may be detected as a defective sensor or cable break. See more in depth article for further differences (click here) T4.0 replacing TX and XR


Q. What it the new HART version?

A. The HART protocol version is essentially a 6th model (output type) with a suffix after the optical specification of -6.


Q. Does the T4.0 HART version communicate with DTMDv6 via HART protocol?

A. Yes.


Q. Do you recommend a specific HART adapter?

A. Yes, the ProComSol, model HM-USB-ISO.


Q. I have an old style HART/RS232 adapter used with a Raytek TX, is this compatible with T4.0

A. Yes.


Q. Is this TX HART adapter XXXTXACRCK (2446074) still available to purchase.

A. No, although in the price list, the status is set to "service replacement only".


Q. Which version of DTMD supports T4.0 with HART protocol.

A. 6.1.94


Q. DTMD 6.1.94 is not available to download, where can I find it?

A. We can send it to you on request until the website is updated.


Q. Does the HART version also have the emissivity encoder switches on the rear panel?

A. No


Q. Does the HART version have a USB port?

A. No. This is for both the -6 and -6-IS versions.


Q. Does the HART version have laser sighting?

A. No. This is for both the -6 and -6-IS versions.


Q. Does the -6 IS version have an alarm output?

A. No, the terminal is present, but the alarm function is deactivated.


Q. Are any other versions available as Intrinsically Safe, like Profinet?

A. No, it is not planned.


Q. Do you recommend a specific HART adapter?

A. Yes, the ProComSol, model HM-USB-ISO.


Q. Where can I buy this adapter?

A. Click this link for a list or distributors


Q. The ProComSol has other adapters, are these compatible?

A. Potentially yes, like the RS232 version, but are not tested.


Q. Does the HART version offer the same addressing and tagging function like the TX:

A. No, tags are not available. Only addresses can be defined. Tags are no longer necessary as for T4.0 (unlike TX) you can have 4-20mA and an address >0/


Q. Does the HART version have a 4-20mA output?

A. Yes


Q. What about information around the pure HART protocol as defined by the FieldComGroup.org, do you have HART device description files?

A. Please see manual T40HART_MA_5277746_ENG_Rev1.0.pdf 


Q. What is the thread size of the protective window?

A. M34 x 1.5 (same as the TX).


Q. I have a T4.0 with Profinet but am unable to communicate with the PLC.

A. First check that the model code ends in - 5. You can make quick test by pinging 192.168.42.134. If you receive a response, this indicates that the Profinet firmware was not loaded. You can also check the firmware revision using DTMD. Profinet firmware is 01.02.1008. Please raise a ticket where we will provide the correct firmware for uploading into the sensor.


Q. When did DTMD start supporting T4.0?

A. v6.0


Q. How does "Field Calibration" work with T4.0?

A. The field calibration function in DTMD v6 is a tool built in to the software for calculating and updating the standard offset and gain parameters (DO and DG) in the device (any "supported" device with offset and gain parameters).  1 point (offset) and 2 point (offset and gain) options are available. After running through the steps of the routine, the offset and gain value are uploaded to the device). These parameters can further be adjusted incrementally via the parameter list.


Q. What connections can I use to run Field Calibration?

A. Any standard way that you connect to DTMDv6 (USB, RS485, Ethernet).


Q. Is there any advantage to any particular connection type?

A. Generally no - except that if there is a very long interval between calibration setpoints due to waiting for a reference source to heat and or cool down, then the ethernet connection may time out during the routine. This may be problematic for 4 pin versions. Note that Profinet and EthernetIP versions can connection to DTMD via the ethernet connection.


Q. How does "Field Calibration" work with T4.0 regarding industrial protocols?

A. Offset and gain values can be defined in the initialization parameters in the respective "project". If the sensor has non-default offset and gain values set before installing into an industrial protocol system, care is needed to ensure that these offset and gain parameters are matched in the project, otherwise the standard values will overwrite the set values. As these values are defined only as initialization parameters, it is not possible to adjust these incrementally or "on the fly" like emissivity or transmissivity:



Q. I have a 2-wire version with emissivity encoder switches. When I select a lower emissivity, the temperature does not change.

A.  1st check that the object is not the same temperature as the ambient temperature. When both are equal, lowering the emissivity will not result in a change. Otherwise, using DTDM v6, check the Emissivity Source parameter. With Rotary switch selected you will see (after updating the parameter list) a change in the value Currently calculated emissivity.



Q. If I change the emissivity parameter setting in the software when Emissivity Source is set to Rotary switch, will the parameter change. Yes and no. You will see the value at Emissivity change, but there will be no effect. You will need to change Emissivity Source to Internal Value





Q. Can I use the XR water cooled jacket with T4.0

A.  Yes. The XR and T4.0 both have a 42 diameter housing and the jackets share the same dimension of 63mm diameter and 108mm length.


Q. Can I use DTMD  5.4.1 with Thermalert 4.0

A.  No


Q. Which is the earliest version of DTMD v6  that is compatible

A.  v6.0 (previously Endurance software)


Q. Table 10-21 of the Thermalert 4.0 manual shows two different transmissivity values of 0.62 and 0.71 for ZnS material?  Is this correct?

A.  The difference in the transmissivity values is due to the different optical models behind. SF and CF provide different optical paths.  With an attached protective window these geometries are not optimal any longer because a part of the incoming IR energy is blocked. This results in different effective transmissivity given in the table. So the root cause of the different values is not the material itself but the limited opening for the optical paths.


Additionally, the  LT-15-SF0 model is a bit special compared to the other SF models because it uses a plastic lens which requires a dedicated lens holder. As a result, the optical path for that unit is already restricted and can not be compromised more when using a protective window.


Q. Can a T4.0 fit in an old Thermojacket (TJ) from a Marathon, TX, MM etc

A. Yes, you need to buy the adapter kit A-TJ-T40-CKIT


Q. Can I reuse the TJ adapters from a TX or XR for a T4.0

A. Yes and no. You can use the nose adapter but no the rear adapter - you still need to buy the kit as the rear adapter is not available separately:



Q. Can I use my existing TX Airpurge collar  P/N  XXXTXXACAP to  Thread   onto a T.40  instead of T4.0 Airpurge P/N A-AP 

A. Yes  

 TX and  T.40  Airpurge Thread size are the same.

Note>  One difference  between the 2  (  Make up Material of the Housing )

XXXTXXACAP       Anodized 

A-AP                    Stainless Steel 


Q. Can I use my existing  TX Pipe Adapter P/N  TX P/N  XXXTXXACPA instead of a T4.0 P/N A-PA

A. Yes 

TX and  T.40  Pipe Adapter Thread size are the same.

Note>  One difference  between the 2  (  Make up Material of the Housing )

XXXTXXACAP    Anodized 

A- PA                Stainless Steel