A
Hi, I'm having problems with temperature readings. I'm using a Mitsubishi FX2n PLC with 3 thermocouples extension block (fx2n-4ad-tc). Each block has 4 channels, so i can read 12 independent temperatures.
The system controls the temperature of a zone of a pipe line, the thermocouple is welded to that pipe line zone or just moored, so the thermocouple is grounded.
The measurement circuit is as follows:
Thermocouple->male connector->female connector->extension cable (like 20 meters)->male connector->female panel connector->compensated cable (like 1 meter)->thermocouple block channel (fx2n-4ad-tc).
All cables and connectors are K type.
The following problems happen independently for differents sets of thermocouples (differents pipe lines) and for anyone of the three blocks:
1 - When only one block's channel is used, the reading is OK, but when i connect other channel of the same block the reading of the first channel goes down about 30-40 Celcius.
2 - When two or more channels seems to work fine, a temperature drop happen suddenly of about 80 Celcius when they reach the 600 Celcius app.
3 - Slow oscillations readings happen when two or more channels are used.
Thanks.
The system controls the temperature of a zone of a pipe line, the thermocouple is welded to that pipe line zone or just moored, so the thermocouple is grounded.
The measurement circuit is as follows:
Thermocouple->male connector->female connector->extension cable (like 20 meters)->male connector->female panel connector->compensated cable (like 1 meter)->thermocouple block channel (fx2n-4ad-tc).
All cables and connectors are K type.
The following problems happen independently for differents sets of thermocouples (differents pipe lines) and for anyone of the three blocks:
1 - When only one block's channel is used, the reading is OK, but when i connect other channel of the same block the reading of the first channel goes down about 30-40 Celcius.
2 - When two or more channels seems to work fine, a temperature drop happen suddenly of about 80 Celcius when they reach the 600 Celcius app.
3 - Slow oscillations readings happen when two or more channels are used.
Thanks.