Hi,
I know this might not be the right place to ask this but I'm kinda stuck and haven't come across anywhere more likely yet.
Basically what I'm trying to do is time the acceleration of an encoder. I have a PCI card in my Windows PC but it's not a counter card so isn't capable of the timing I need. It has a couple of fast counters and some digital inputs and outputs.
The encoder is a Hengstler RI38 with A,B and Z outputs, these are pushpull type. So 50 times a revolution the encoder sends a pulse on the A line. What I want to do is feed this A input into the CLOCK side of a JK flipflop with the J and K inputs tied. The result being that when the encoder sends its first pulse the output of the JK will be 1 and will stay 1 until the next pulse when it will toggle to 0 and so on.
I've tested my JK flipflop with a slow 555 timer pulse and what I'm looking for works fine, but when I connect in the encoder things start to go a bit mad. Spinning the encoder is causing the flipflop to toggle without me even connecting the encoder to the flipflop, it seems to be coming through ground or +5V. Basically I think I have some sort of noise issue or I have completely misunderstood how to connect the encoder to a TTL circuit. With a probe on the 555 timer I see a LOW signal as 0V and HIGH as about 5V, but from the encoder a LOW seems to be about 0.6V and a high somewhere over 4V.
Does anybody know what I'm doing wrong here? Do I need pull up or pull down resistors? This kind of thing isn't my speciality so I imagine one of you gurus will look at it and wonder why the hell I forgot to connect component X to connection Y .
Any and ALL help much appreciated!
I know this might not be the right place to ask this but I'm kinda stuck and haven't come across anywhere more likely yet.
Basically what I'm trying to do is time the acceleration of an encoder. I have a PCI card in my Windows PC but it's not a counter card so isn't capable of the timing I need. It has a couple of fast counters and some digital inputs and outputs.
The encoder is a Hengstler RI38 with A,B and Z outputs, these are pushpull type. So 50 times a revolution the encoder sends a pulse on the A line. What I want to do is feed this A input into the CLOCK side of a JK flipflop with the J and K inputs tied. The result being that when the encoder sends its first pulse the output of the JK will be 1 and will stay 1 until the next pulse when it will toggle to 0 and so on.
I've tested my JK flipflop with a slow 555 timer pulse and what I'm looking for works fine, but when I connect in the encoder things start to go a bit mad. Spinning the encoder is causing the flipflop to toggle without me even connecting the encoder to the flipflop, it seems to be coming through ground or +5V. Basically I think I have some sort of noise issue or I have completely misunderstood how to connect the encoder to a TTL circuit. With a probe on the 555 timer I see a LOW signal as 0V and HIGH as about 5V, but from the encoder a LOW seems to be about 0.6V and a high somewhere over 4V.
Does anybody know what I'm doing wrong here? Do I need pull up or pull down resistors? This kind of thing isn't my speciality so I imagine one of you gurus will look at it and wonder why the hell I forgot to connect component X to connection Y .
Any and ALL help much appreciated!