Hi PLC experts!
I need advice and your suggestions. I have Schneider's PLC Zelio SR3B261FU Smart relay. It is used to run 2 water pumps.
INPUTS
IN1 - AUTO P1
IN2 - MANUAL P1
IN3 - AUTO P2
IN4 - MANUAL P2
Inputs are connected through selector switch (1-0-2) and physically cannot be selected MANUAL and AUTO in the same time for a pump.
Inputs IN1 and IN2 are fine and reacting on switching very fine.
Issue is with IN3 and IN4. They are ALWAYS ON (BOTH together). Selector switch is tested and is ok. I removed wires from IN3 and IN4 but they still didn't change value (ON).
I tried to reset voltage powering relay ("plc") and after boot up, inputs are ok and in state OFF. But after some time they turn ON by itself. I tried to measure voltage between Inputs and GND and here are results:
IN1 - GND - 38VAC
IN2 - GND - 38VAC
IN3 - GND - 39,9 VAC
IN4 - GND - 39,9 VAC
It is little bit strange as it should be very near 0VAC if I'm right. From datasheet it can be seen that Voltage state 0 is guaranteed <= 40 V for discrete input. IN3 and IN4 are very very close to the limit value and it can cause an issue.
If I force Inputs to change bit value, it works good.
Do you have any more suggestions what to test and to check? Ground fault? Zelio faults?
Thank you!
I need advice and your suggestions. I have Schneider's PLC Zelio SR3B261FU Smart relay. It is used to run 2 water pumps.
INPUTS
IN1 - AUTO P1
IN2 - MANUAL P1
IN3 - AUTO P2
IN4 - MANUAL P2
Inputs are connected through selector switch (1-0-2) and physically cannot be selected MANUAL and AUTO in the same time for a pump.
Inputs IN1 and IN2 are fine and reacting on switching very fine.
Issue is with IN3 and IN4. They are ALWAYS ON (BOTH together). Selector switch is tested and is ok. I removed wires from IN3 and IN4 but they still didn't change value (ON).
I tried to reset voltage powering relay ("plc") and after boot up, inputs are ok and in state OFF. But after some time they turn ON by itself. I tried to measure voltage between Inputs and GND and here are results:
IN1 - GND - 38VAC
IN2 - GND - 38VAC
IN3 - GND - 39,9 VAC
IN4 - GND - 39,9 VAC
It is little bit strange as it should be very near 0VAC if I'm right. From datasheet it can be seen that Voltage state 0 is guaranteed <= 40 V for discrete input. IN3 and IN4 are very very close to the limit value and it can cause an issue.
If I force Inputs to change bit value, it works good.
Do you have any more suggestions what to test and to check? Ground fault? Zelio faults?
Thank you!