I'm hoping I can get some input from you folks here.
I have been working on and off in Automation for over a decade, mostly with Siemens PLCs. I am currently working with a small R&D automation team with (other than myself) more-or-less no PLC experience, the assembly process we are trying to automate is extremely complex, involves robotic assembly, and until now has been PC controlled (with manual intervention). One of the guys in the team has a computer science background, and has written the PC interfaces to CANopen, RS232 and a TCP server for communicating with various components, and the robot PC program has handled the rest of the control through user I/O. The HMI was written in some other programming language and interacts with the rest of the process through TCP connection. Since I joined this team a little while ago, we've begun migrating everything over to PLC control, as we've regularly been asked from people outside why we're not using PLC control, and I felt that certain things may be more easily and effectively handled via PLC (CANopen control of drives, fault handling and further HMI development, for example). Also our techs aren't computer scientists/programmers so should reading code ever be necessary, monitoring a ladder PLC program seemed to make more sense to me.
So far everything has been working out fine, but due to the extensive numbers of robot sequences required, different interfaces and other features of the system, the PLC program has become much much more than just (is it ever?) bit logic (mainly using string commands routed around to control components). While doable, the computer science guy is of the opinion that PLC control is an archaic relic of times gone by, and feels that the things we're trying to do are so much more easily implemented on a PC. I don't really have a good counter-argument; so far I've been able to implement everything fine, but we're coming at this from two different angles ... my argument has been for PLC control because theres no worry about a blue screen of death in the middle of a production sequence, the controls are robust and will last forever, and the programs can be more easily monitored by our techs. But he brings up examples of other companies with complex automation using things like labview for control. While my gut feeling is that this is like comparing hobbiest equipment vs. industry, I can't really argue with him from the high level language or ease of implementation standpoint.
So I'm curious, anyone have any input in defense of one argument or the other? Input from all different industries is welcome. And this also brings up another question ... where is the line drawn when deciding what parts of a system should be PLC controlled and what should be controlled by an industrial PC?
I have been working on and off in Automation for over a decade, mostly with Siemens PLCs. I am currently working with a small R&D automation team with (other than myself) more-or-less no PLC experience, the assembly process we are trying to automate is extremely complex, involves robotic assembly, and until now has been PC controlled (with manual intervention). One of the guys in the team has a computer science background, and has written the PC interfaces to CANopen, RS232 and a TCP server for communicating with various components, and the robot PC program has handled the rest of the control through user I/O. The HMI was written in some other programming language and interacts with the rest of the process through TCP connection. Since I joined this team a little while ago, we've begun migrating everything over to PLC control, as we've regularly been asked from people outside why we're not using PLC control, and I felt that certain things may be more easily and effectively handled via PLC (CANopen control of drives, fault handling and further HMI development, for example). Also our techs aren't computer scientists/programmers so should reading code ever be necessary, monitoring a ladder PLC program seemed to make more sense to me.
So far everything has been working out fine, but due to the extensive numbers of robot sequences required, different interfaces and other features of the system, the PLC program has become much much more than just (is it ever?) bit logic (mainly using string commands routed around to control components). While doable, the computer science guy is of the opinion that PLC control is an archaic relic of times gone by, and feels that the things we're trying to do are so much more easily implemented on a PC. I don't really have a good counter-argument; so far I've been able to implement everything fine, but we're coming at this from two different angles ... my argument has been for PLC control because theres no worry about a blue screen of death in the middle of a production sequence, the controls are robust and will last forever, and the programs can be more easily monitored by our techs. But he brings up examples of other companies with complex automation using things like labview for control. While my gut feeling is that this is like comparing hobbiest equipment vs. industry, I can't really argue with him from the high level language or ease of implementation standpoint.
So I'm curious, anyone have any input in defense of one argument or the other? Input from all different industries is welcome. And this also brings up another question ... where is the line drawn when deciding what parts of a system should be PLC controlled and what should be controlled by an industrial PC?