8/30/2010 9:03 AM | |
Posts: 2930 Rating:
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Hi, the inputs works as a AI or a DI depending of your programm. If you program AI1 (I7) with an analog comparator but connect 24V DC to the inpout, then the Value will be 1000. You can use both at the same time. See attached program. If you analog value exeed the value of a digital "1", the the digital "path" works. If this value is lower then 10V, then your analog path works normal up to the value 1000. Please observe, the value where LOGO! react for a digital "1" is variable. The manual includes the value where LOGO! always recognice a dig. "1". In reality it is ~ 6V on a LOGO! 12/24RC.. Check this out: Hope this helps AttachmentAI and DI at same time.zip (415 Downloads) |
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8/30/2010 1:04 PM | |
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Helmut_13 has the right idea. You CAN use the analog inputs and the digital inputs at the same time in a program.... BUT..... You must be VERY CAREFUL about how they will react in your program. On a LOGO! 24C or 24Co, the digital inputs are defined in the specifications as - signal 0: < 5V - signal 1: > 12V (because this LOGO! is expecting digital inputs of 24V DC) THEREFORE, your analog input signal between 0-24V DC will generate a corresponding analog signal change between 0...1000 inside the LOGO! as an anlaog input (eg. AI1 on I7), but only while it is in the range 0..10V DC (or maybe up to max. 12V DC). Around about 12V DC, the digital input I7 will go 'hi'. It is not exactly defined that it will switch at exactly this threshold, but you could experiment with it. BE CAREFUL!!! In the spec's, it also shows that the analog capable inputs (I1,I2,I7 & I8) also have a MUCH LOWER current sensitivity than the other digial inputs, with an input impedance of 72 kOhm On a LOGO! 12/24RC or 12/24RCo, the digital inputs are defined in the specifications as - signal 0: < 5VDC - signal 1: > 8.5 VDC (because it is expecting digial inputs of 12..24V DC) THEREFORE, your analog input signal between 0-24V DC will generate a corresponding analog signal change between 0...1000 inside the LOGO! as an anlaog input (eg. AI1 on I7), but only while it is in the range 0..10V DC. Around about 8.5V DC, the digital input I7 will go 'hi'. It is not exactly defined that it will switch at exactly this threshold, but you could experiment with it. Using the digital input as an anlog input at the same time is TRICKY!!! It will work quite fine as an analog input for the 0..10 V DC part of your analog signal. The analog signal (internal) will stay fixed at 1000 for analog signals above 10V DC (up to 24V DC). On a LOGO! 24C(o), the same input will switch 'digitally' at about 12V DC to '1' On a LOGO! 12/24RC(o), the same input will switch 'digitally' at about 8.5V DC to '1' In this way, the digial inputs behaves like an 'Analog threshold trigger' with BOTH the threshold values set to999 (24C(o)) or 849 (12/24RC(o)) if the sensor type is selected as 0..10V. (see attachment). Maybe you could use these in your program in this way. BUT If you have an analog signal that is sitting at maybe 5,71 VDC (571 internal value) and you have a switch also connected to the input that then gets switched (to either 12 V DC or 24 V DC), then as a digital input it will go to '1', but the analog value (internal) will go to 1000, and this could have some bad effects on your program! All the best! AAAAArrrrggghhhh!!! ("Have a nice day!") AttachmentAI_DI_together.zip (354 Downloads) |
Last edited by: LOGO!Barbarian at: 8/30/2010 1:21 PMOooops!!! Forgot the attachement! Silly me !! |
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