GaryS
Member
I did miss the 40K counts but who makes a 10K PPR encoder all the ones I have seen are 6K PPR or 24K counts max and they are hard to find
As for the HSC's the have been around for abut 30 years, one of the input words is real time frequency that you can set the update time for as low as 10 ms but for better accuracy you should set them close to the PLC read update time interval. most IO update are set at 100 ms default
A simple math function will convert to whatever you rate you need.
I have done it many times
As for the outputs on the HSC modules they can be configured to be controlled by the PLC and updated on the normal update scan or you can configure them to be controlled by the HSC module computer, you set them to turn ON and OFF based on the internal counts of the counter you want depending on how you setup the HSC module.
If the module is controlling the output the PLC can only look at their state at the normal IO scan
It is possible to have an output turn on and back off between the IO scan and the PLC will never be aware of it. I set them up all the time to control a feed solenoid based on a flow meter counts since they work outside of the scan time the are much more accurate and repeatable then what you could get through the PLC and IO scan.
It's been a while but I think with a single counter active the input pulse rate is 100 mhz I would have to look it up. It all in the manual
As for the 18 Bit absolute encoder they have been out their for many years and I think the 24 Bit and 32 Bit encoders are are more available and I am sure that their is a 64 Bit absolute encoder out their most of those also have a pulse output that you can use to monitor rate or speed if needed. If the encoder is mounter directly on the motor it works better but has a limited number of motor revolutions.
but all the absolute encoder have a built in design problem and that's slippage on contact wheels, that slippage changes with environmental change a temperature change can cause a measuring wheel diameter change in the measuring wheel, moisture in the air can cause slippage, dirt n the contact surface can change the travel distance. All of this should be considered when designing the system.
And them you have the problem with the cables the constant movement will cause the cable to break down. I had a client that always changed the cable at least every 2 years and they still had the problems I listed above
The best way to measure position and rate is with a good laser measuring system I did a crane system the travel was over 1,000 ft and we were accurate to about .10 in
and no maintenance issues. With the new ones you get a digital position back to the PLC scaled and ready for you to use.
Use an encoder for short distance measuring and speed feedback to have good stable speed control.
I have seen laser systems that will read distance to within a foot at at the horizon
This little project would be interesting to do but not difficult just put the right hardware together
Do let up know how you make out on this
As for the HSC's the have been around for abut 30 years, one of the input words is real time frequency that you can set the update time for as low as 10 ms but for better accuracy you should set them close to the PLC read update time interval. most IO update are set at 100 ms default
A simple math function will convert to whatever you rate you need.
I have done it many times
As for the outputs on the HSC modules they can be configured to be controlled by the PLC and updated on the normal update scan or you can configure them to be controlled by the HSC module computer, you set them to turn ON and OFF based on the internal counts of the counter you want depending on how you setup the HSC module.
If the module is controlling the output the PLC can only look at their state at the normal IO scan
It is possible to have an output turn on and back off between the IO scan and the PLC will never be aware of it. I set them up all the time to control a feed solenoid based on a flow meter counts since they work outside of the scan time the are much more accurate and repeatable then what you could get through the PLC and IO scan.
It's been a while but I think with a single counter active the input pulse rate is 100 mhz I would have to look it up. It all in the manual
As for the 18 Bit absolute encoder they have been out their for many years and I think the 24 Bit and 32 Bit encoders are are more available and I am sure that their is a 64 Bit absolute encoder out their most of those also have a pulse output that you can use to monitor rate or speed if needed. If the encoder is mounter directly on the motor it works better but has a limited number of motor revolutions.
but all the absolute encoder have a built in design problem and that's slippage on contact wheels, that slippage changes with environmental change a temperature change can cause a measuring wheel diameter change in the measuring wheel, moisture in the air can cause slippage, dirt n the contact surface can change the travel distance. All of this should be considered when designing the system.
And them you have the problem with the cables the constant movement will cause the cable to break down. I had a client that always changed the cable at least every 2 years and they still had the problems I listed above
The best way to measure position and rate is with a good laser measuring system I did a crane system the travel was over 1,000 ft and we were accurate to about .10 in
and no maintenance issues. With the new ones you get a digital position back to the PLC scaled and ready for you to use.
Use an encoder for short distance measuring and speed feedback to have good stable speed control.
I have seen laser systems that will read distance to within a foot at at the horizon
This little project would be interesting to do but not difficult just put the right hardware together
Do let up know how you make out on this