Looking for suggestions on a pathway for a high speed, variable frequency output for a slitter line. There is a corporate data collection system that is some knockoff brand and is expecting some high speed pulse input to measuring production speed.
We cannot use standard logic with timers as this system is expecting a 10-1500hz *variable* signal and scan time can not flick the standard outputs off/on fast enough.
We tried to implement a PWM output from the 1734-VHSC ouptut module, however it has a fixed frequency but variable duty (length of time output is high). I have found lots of plc input cards for variable frequency inputs, but nothing to compare for a output. This VHSC module can have clock speed changed in the module properties, however it requires disable/re-enable module and will not be dynamic with process flow while that change is being made.
This system needs to be dynamic so when the line is creeping at startup for 10ft/min we get a pulse frequency of 10hz and when it is at max speed of 900ft/min we get a frequency of 900hz. These are generic numbers and we can scale down on the data collection side, however it cannot be scaled up (we can make 10 pulses=1ft/min, but we can't make 1 pulse=10ft/min)
The end of the day our result might be hooking an encoder to the input for direct line speed, however I would prefer not to install another mechanical device that can get bypassed or broken when we have a very accurate speed already in the plc itself. It's too bad this knockoff data collection system will not allow us to message a value directly...
We cannot use standard logic with timers as this system is expecting a 10-1500hz *variable* signal and scan time can not flick the standard outputs off/on fast enough.
We tried to implement a PWM output from the 1734-VHSC ouptut module, however it has a fixed frequency but variable duty (length of time output is high). I have found lots of plc input cards for variable frequency inputs, but nothing to compare for a output. This VHSC module can have clock speed changed in the module properties, however it requires disable/re-enable module and will not be dynamic with process flow while that change is being made.
This system needs to be dynamic so when the line is creeping at startup for 10ft/min we get a pulse frequency of 10hz and when it is at max speed of 900ft/min we get a frequency of 900hz. These are generic numbers and we can scale down on the data collection side, however it cannot be scaled up (we can make 10 pulses=1ft/min, but we can't make 1 pulse=10ft/min)
The end of the day our result might be hooking an encoder to the input for direct line speed, however I would prefer not to install another mechanical device that can get bypassed or broken when we have a very accurate speed already in the plc itself. It's too bad this knockoff data collection system will not allow us to message a value directly...