I am looking to automate an old machine + integrate Data Aquisition and I am considering LabVIEW. I have never used it before; just heard about it from someone else.
The machine is a pull tester for cables. a 20ft section of cable is clamped at one end and tension is applied to it by a hydraulic ram on the other end. around the cable are large heaters to heat it up while stretching it.
here's what I got:
· heating is controlled in 6 zones by 6 separate Watlow 985 PID temperature controllers.
· Tension is applied hydraulically via increase & decrease pushbuttons & read out on a digital display. increase/decrease operation is very hard to control and not precise; often overshooting.
· Data Acquisition is via an Agilent 34970A DAQ unit, measuring ovality, diameter, and other parameters
Current operator process is as follows:
1. Operator will set all 6 heat zone controllers to the maximum heat specification for the cable under test (variable) & wait for all 6 temperatures to stabilize
2. operator will apply tension up to the maximum specification for the cable under test (variable)
3. operator will drop the temperature on all 6 zones to room temperature and wait for temp to stabilize
4. Operator will increase tension from 0lbs to max tension spec for the cable under test (variable, 5000lbs-10,000lbs), stopping 20 - 35 times (20-35 more variables) along the way and capture readings via the Agilent DAQ unit.
5. Operator will increase heat on all 6 zones from room temperature to 150F and redo step 4. Then increase to 225F and redo step 4, and so on for temps of 300F and 350F, maybe more.
even though the only requirements are to apply pressure, heat, and start/stop a data logger, we are dealing with possibly hundreds of variables, and a single sequence with possibly hundreds of steps that may take all day. Also, considering this machine is used by engineering, I anticipate that the way in which it is used (the variables as well as the steps) will vary greatly throughout its life, so a high degree of flexibility is need here. Technically it should be possible to automate with a PLC (the Agilent DAQ appears to accept an outside trigger to start/stop logging), but personally, I do not think that a PLC is the way to go. Using a PLC would be exceedingly complicated and would mean also needing an HMI to input all these variables and I can see myself going to reprogram it monthly or weekly; any time the engineers desire a different operation from it. a friend has suggested using a PC-based platform called LabVIEW. I have not used LabVIEW before but a brief review of it looks promising. It looks heavier on the Data Acquisition side than the process automation side, but it is has analog & digital output hardware so it is probably still up to the task. Graphical block programming, easy interface to hardware; the Engineers could modify the process themselves, as well as integrate the data acquisition into the process.
This Alicat PCD Series valve/controller combo can be controlled by potentiometer or RS232 devices (PLC), and also has a ready-made driver for LabVIEW. The Watlow 985 controllers accept no external setpoint reference, so I recommended upgrading them to Eurotherm 3208 controllers; these are same-size drop in replacements that have RS232 comms ability + ready-made LabVIEW drivers
So, I am looking for anyone with LabVIEW experience to validate me barking up this tree or send me to another one. Can LabVIEW be used to automate my machine? thanks
The machine is a pull tester for cables. a 20ft section of cable is clamped at one end and tension is applied to it by a hydraulic ram on the other end. around the cable are large heaters to heat it up while stretching it.
here's what I got:
· heating is controlled in 6 zones by 6 separate Watlow 985 PID temperature controllers.
· Tension is applied hydraulically via increase & decrease pushbuttons & read out on a digital display. increase/decrease operation is very hard to control and not precise; often overshooting.
· Data Acquisition is via an Agilent 34970A DAQ unit, measuring ovality, diameter, and other parameters
Current operator process is as follows:
1. Operator will set all 6 heat zone controllers to the maximum heat specification for the cable under test (variable) & wait for all 6 temperatures to stabilize
2. operator will apply tension up to the maximum specification for the cable under test (variable)
3. operator will drop the temperature on all 6 zones to room temperature and wait for temp to stabilize
4. Operator will increase tension from 0lbs to max tension spec for the cable under test (variable, 5000lbs-10,000lbs), stopping 20 - 35 times (20-35 more variables) along the way and capture readings via the Agilent DAQ unit.
5. Operator will increase heat on all 6 zones from room temperature to 150F and redo step 4. Then increase to 225F and redo step 4, and so on for temps of 300F and 350F, maybe more.
even though the only requirements are to apply pressure, heat, and start/stop a data logger, we are dealing with possibly hundreds of variables, and a single sequence with possibly hundreds of steps that may take all day. Also, considering this machine is used by engineering, I anticipate that the way in which it is used (the variables as well as the steps) will vary greatly throughout its life, so a high degree of flexibility is need here. Technically it should be possible to automate with a PLC (the Agilent DAQ appears to accept an outside trigger to start/stop logging), but personally, I do not think that a PLC is the way to go. Using a PLC would be exceedingly complicated and would mean also needing an HMI to input all these variables and I can see myself going to reprogram it monthly or weekly; any time the engineers desire a different operation from it. a friend has suggested using a PC-based platform called LabVIEW. I have not used LabVIEW before but a brief review of it looks promising. It looks heavier on the Data Acquisition side than the process automation side, but it is has analog & digital output hardware so it is probably still up to the task. Graphical block programming, easy interface to hardware; the Engineers could modify the process themselves, as well as integrate the data acquisition into the process.
This Alicat PCD Series valve/controller combo can be controlled by potentiometer or RS232 devices (PLC), and also has a ready-made driver for LabVIEW. The Watlow 985 controllers accept no external setpoint reference, so I recommended upgrading them to Eurotherm 3208 controllers; these are same-size drop in replacements that have RS232 comms ability + ready-made LabVIEW drivers
So, I am looking for anyone with LabVIEW experience to validate me barking up this tree or send me to another one. Can LabVIEW be used to automate my machine? thanks