Hi all,

I need to capture some very short signal length IO, like clicker wrenches, and such...in the past I've seen AB has some signal stretcher that holds the signal on for 10-100ms. What are some options that Siemens offering, hardware and software.

Thanks in advance

 

I don't know if this is an option, but we use Keyence Fiber optic sensors which can capture a 30-50us event (depending on model) and you can program an off delay in milliseconds. I usually set all the signals by default to 5ms but you will need more time delay if your PLC IO or scan is slower than this.

OMRON also makes a very small 24VDC timer relay that fits on a DIN rail. Their prices are good but you will have to check on their input response. I believe it is solid state, but you need to check the numbers.

KEJR

 

You can also, with proper scaling use a TTL or CMOS latch which will "catch" signals down to nanoseconds. And they're very inexpensive.

Regards
cww

 

This is a good idea, but make sure you optically isolate the IO and filter the power. Sometimes TTL can be too fast for industrial apps. Capacitively coupled noise spikes from neighboring lines can induce several volts of noise. If you design with optical isolation and shoot for the switching threshold to be about 10-14V you will have many volts of noise margin on either side of the threshold. Even if you don't optically isolate design for these switching thresholds.

KEJR