XGB Analog edition manual 
 
4.9 Disconnection Detection Function 
 
(1)  As a module used to measure the temperature with the  RTD  temperature sensor directly 
connected, it detects and displays disconnection of the sensor connected. If any disconnection 
occurs in the sensor used and extended lead wire, LED (ALM) will flicker in a cycle of 1 second 
and produce an error code. 
 
(2) Disconnection can be detected per channel, however, only for the channel specified to run. 
   LED (ALM) is used in common for all the channels. It will flicker if one or more channels are 
disconnected.   
 
(3) The figure below shows the temperature sensor’s appearance of the 3-wired RTD.   
(The appearance depends on sensor type)   
 
 
 
 
 
   
* A disconnection: if disconnected between terminal A and terminal board of the module in the   
sensor figure. 
* B disconnection: if disconnected between terminal B (two for 3-wired sensor) and terminal   
board of the module in the sensor figure, or if A and B lines are all disconnected. 
 
(4) The basic connection between RTD module and RTD Sensor is based on 3-wired RTD sensor. 
If 2-wired or 4-wired sensor is used, the connection between the sensor and the module shall be 
kept as 3-wired. Disconnection will be detected on the basis of 3-wired wiring. 
 
   (5) In case of disconnection, status of ALD LED and operation of disconnection flag are as follows. 
     - For disconnection flag, refer to 12.3.14 internal memory. 
Connection status 
Channel 
status 
  ALM LED 
status 
Disconnection 
flag 
Normal 
Run  Off  Off 
Stop  Off  Off 
A line disconnected or   
B line disconnected 
Run  Flicker (1s)  On 
Stop  Off 
 
Off 
Any sensor is not 
connected 
Run  Flicker (1s) 
 
On 
Stop  Off  Off 
 
 
 
 
 
 
 
 
B 
b 
A 
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