Sensor under range mA output difference


When the T4.0 (all models) is underrange the mA output will drop to 3.5mA (TX was 3.99mA). With some control systems , this may be detected as a defective sensor or cable break. This is less of a problem when replacing XR as the output would fall to 2.5mA with the XR and any control system considerations would likely have considered this


Water cooling with T4.0 is the same as XR, as an accessory water jacket, where TX water cooling was a build option. 


Form Factor


Please ensure to consider the correct connection scheme:




Warning:


Without detailed consideration of the customer's control system and the possibility to modify the scheme:


Never replace a TX with a 6-wire or 12-wire T4.0 - you will damage the mA output of the T4.0 if you connect it to a "2-wire" connection  (loop powered control system).


Never replace an XRT or XRC (4-wire analog sensor) with a T4.0 2wire/-0 version - you won't damage the sensor but  it will appear to not function as the mA input connections to the PLC are not loop powered and will not power the sensor. In many cases you can reconfigure a PLC input between 2 and 4 wire.


Special note on XR:

We had reports from one OEM that they had, for many years, connected the mA output of their XR to a 2-wire loop powered PLC input. Upon investigation we found that they had also reversed the polarity to the PLC connection. This was considered a quirk of the XR design and the over engineered output circuit protection (it was never part of the design specification).


We know 100% that the T4.0 will not operate in the same way (it may appear to but will fail in a short or very short time). It was not designed to and will not be modified to do so in the future.