profibus Control
profibus Control
(OP)
Can Profibus replace the hardwired for the motor contro? As a plant operator, I haven't got convinced not to use hardwired control for start-stop of the motors, especialy for large motors.
Can somebody make some commments?
Thanks in advance.
Can somebody make some commments?
Thanks in advance.






RE: profibus Control
RE: profibus Control
If we are not speaking of Safety Systems, there are ways to implement Profibus control with a quasi-manual system that can take control if the Profibus comm signal is lost. One nice thing about Profibus is its ability to self-monitor. I use Siemens Simocode relays on large motors as the protection device and control interface. They have the ability to be controlled by a Profibus network on normal operations, but they use the network monitoring function to automatically allow for manual hard-wired control if the network ever goes down. In fact I set them up to be seamless transfer in most cases and I always program them to allow a hard wired E-stop to override any Profibus command, unless a disorderly shutdown will have worse consequences than an E-stop.
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RE: profibus Control
RE: profibus Control
RE: profibus Control
But in my opinion, ProfiBus might be better for motor controls because it is deterministic and most Ethernet TCP/IP based networks are not. An exception to that I know of is the ProfiBus version of Ethernet, called ProfiNet. They add deterministic data to the standard TCP/IP protocol packets to make it more deterministic, but most people consider it slightly less so than ProfiBus because of the inherent nature of Ehternet to start with. In sub-station automation this may not be an issue, with motor controls it might. You would have to evaluate what that means to you.
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
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RE: profibus Control
Would you consider to use Profibus to control the motor only without any hardwired control?