SiriusMark
Member
Okay, here goes nothing....
I need to pull a speed measurement into an existing PLC. This is on a diesel generator and the existing Tachometer is a Dynalco SPD-100 which measures in frequency. Is there a method of splicing onto this line and running a parallel leg into an analog input card on a SLC 5/03?
I'm making this stuff up as I go, if it is simply impossible, let me know. The goal is to be able to provide a speed measurement into the PLC that can be used in series with the oil pressure sensor.
Right now, when we shut the generator down, the low oil pressure kicks off the safety shutdown relay, which must then be reset manually. A lot of personnel who have access to the controls don't bother to notice that the relay has opened. This wouldn't be a serious problem except that it is our standby generator and if no one notices the relay is out, then the generator won't kick on automatically in case of a failure of our main. My idea is to place the low pressure contact in series with a generator speed contact. If the generator is at 90% speed and oil pressure falls below a certain figure, both conditions are true and there is a fault. If the oil pressure falls but the engine speed is at 30%, no fault condition exists.
Except I don't have a speed input to the PLC. Hence the crazy question. Thank you for your time, I'm curious to see what you guys come up with.
I need to pull a speed measurement into an existing PLC. This is on a diesel generator and the existing Tachometer is a Dynalco SPD-100 which measures in frequency. Is there a method of splicing onto this line and running a parallel leg into an analog input card on a SLC 5/03?
I'm making this stuff up as I go, if it is simply impossible, let me know. The goal is to be able to provide a speed measurement into the PLC that can be used in series with the oil pressure sensor.
Right now, when we shut the generator down, the low oil pressure kicks off the safety shutdown relay, which must then be reset manually. A lot of personnel who have access to the controls don't bother to notice that the relay has opened. This wouldn't be a serious problem except that it is our standby generator and if no one notices the relay is out, then the generator won't kick on automatically in case of a failure of our main. My idea is to place the low pressure contact in series with a generator speed contact. If the generator is at 90% speed and oil pressure falls below a certain figure, both conditions are true and there is a fault. If the oil pressure falls but the engine speed is at 30%, no fault condition exists.
Except I don't have a speed input to the PLC. Hence the crazy question. Thank you for your time, I'm curious to see what you guys come up with.