shodhakusa
Member
- Join Date
- Apr 2005
- Posts
- 6
Hi All
I am using SIEMEN's HMI with 24 VDC input ... Supply seems to be sufficient (rated 24V ... 3A...). Last week we connected one NPN
switch across PLC.. used pull up resistor after making all calculation on bennch and now Not sure but some how My HMI is acting up. Problem is not consistent .It just goes blank ....
1. I tried different HMI... same HMI will work outside once this happens and if you put it back it will work again.
2. Siemen's HMI-270 B has input polarity protection so if it sees short it goes blank... but in this case it will be functional many hours and then suddenly this will happen. I could not repeat the fault....
We have pressurized cabinet, regulator set to 1.5 PSI ; switch is set to 0.8 PSI ( It is vacuum switch..) Pull up resistor has been added across PLC have enough value and wattage rating...
Is this something related to pressure or connecting switch... it is 3 wire switch .. one connected to PLC input and other two connected to supply as manufacturer diagram states....
If any one can supply any comments on this that will be great help.. Appreciate...
I am using SIEMEN's HMI with 24 VDC input ... Supply seems to be sufficient (rated 24V ... 3A...). Last week we connected one NPN
switch across PLC.. used pull up resistor after making all calculation on bennch and now Not sure but some how My HMI is acting up. Problem is not consistent .It just goes blank ....
1. I tried different HMI... same HMI will work outside once this happens and if you put it back it will work again.
2. Siemen's HMI-270 B has input polarity protection so if it sees short it goes blank... but in this case it will be functional many hours and then suddenly this will happen. I could not repeat the fault....
We have pressurized cabinet, regulator set to 1.5 PSI ; switch is set to 0.8 PSI ( It is vacuum switch..) Pull up resistor has been added across PLC have enough value and wattage rating...
Is this something related to pressure or connecting switch... it is 3 wire switch .. one connected to PLC input and other two connected to supply as manufacturer diagram states....
If any one can supply any comments on this that will be great help.. Appreciate...