LSIS XGB Series, User Manual, Page: 115 / 618

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
A terminal
B terminal
B
b
A
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