Careful consideration...
Hi Keith,
I can understand your "are you crazy?" vibe for recommending an L8 for Ethernet communications, and of course I would agree; where one is not designing a new application to the control level that might warrant an L8 controller, it may not make sense to consider using one. Overkill, and all that.
However, where one may be designing a larger or more complex application; when scoping out Ethernet intercommunications options, it may be worth considering the L8 to handle certain aspects, or indeed all of the Ethernet traffic required.
In repeating myself, and in how I tend to think, and dispense advice - I am saying that careful consideration should be given where such options, are options. That is, one should consider, carefully, whether it is feasible to use one, or not. I am not suggesting, in any way, that utilizing an L8 controller with embedded Ethernet is a like-for-like option to utilizing a 1756-ENxT module with any other controller. There are indeed many feature differences to be considered.
As I always say, and will continue to say - these decisions should be application dependant. As such, I do not presume to know what application any one individual is or may be designing, while dispensing the above advice. It's not for me to say that some, most, or many won't want to use an L8 for "their" applications. I also think, with respect, that you should not presume to speak for them either. But that of course is your choice here. I believe it should be up to the designer of each unique application to give due and careful consideration to all and any affordable options.
All that is, of course, not mentioning anything to do with affordability, or price comparison here...
In the interest of shedding some light on what rupej has suggested with regard to Rockwell's pricing strategy when considering an L7 and ENxT module combination verses an L8 with embedded Ethernet -
(EDIT - and you now appear to have realized yourself)
This article from Shawn Tierney over on The Automation Blog, while a few years old now, gives both a good quick synopsis of the comparison here, both in main features and pricing...
Price Comparison: 1756-L8 vs 1756-L7
As we can see (albeit using prices of that day), the comparible L8 alone is less expensive than the L7/ENBT combo.
Looking forward to today's prices, over on the PLC Hardware website, and as an example stateside...
A brand new 1756-L75 is $20,200.00 retail price.
A brand new 1756-EN2T is $2,980.00 retail price.
That makes a combined total of $23,180.00.
A brand new 1756-L85E with embedded Ethernet is $20,300.00 retail price.
That is a saving of $2,880.00 while harnessing state-of-the-art features, if suitable to the application, after careful consideration.
Yes, do indeed take another look. You may be pleasantly surprised.
Regards,
George
kamenges said:
Hi Keith,
I can understand your "are you crazy?" vibe for recommending an L8 for Ethernet communications, and of course I would agree; where one is not designing a new application to the control level that might warrant an L8 controller, it may not make sense to consider using one. Overkill, and all that.
However, where one may be designing a larger or more complex application; when scoping out Ethernet intercommunications options, it may be worth considering the L8 to handle certain aspects, or indeed all of the Ethernet traffic required.
Geospark said:
In repeating myself, and in how I tend to think, and dispense advice - I am saying that careful consideration should be given where such options, are options. That is, one should consider, carefully, whether it is feasible to use one, or not. I am not suggesting, in any way, that utilizing an L8 controller with embedded Ethernet is a like-for-like option to utilizing a 1756-ENxT module with any other controller. There are indeed many feature differences to be considered.
kamanges said:
As I always say, and will continue to say - these decisions should be application dependant. As such, I do not presume to know what application any one individual is or may be designing, while dispensing the above advice. It's not for me to say that some, most, or many won't want to use an L8 for "their" applications. I also think, with respect, that you should not presume to speak for them either. But that of course is your choice here. I believe it should be up to the designer of each unique application to give due and careful consideration to all and any affordable options.
All that is, of course, not mentioning anything to do with affordability, or price comparison here...
In the interest of shedding some light on what rupej has suggested with regard to Rockwell's pricing strategy when considering an L7 and ENxT module combination verses an L8 with embedded Ethernet -
(EDIT - and you now appear to have realized yourself)
This article from Shawn Tierney over on The Automation Blog, while a few years old now, gives both a good quick synopsis of the comparison here, both in main features and pricing...
Price Comparison: 1756-L8 vs 1756-L7
As we can see (albeit using prices of that day), the comparible L8 alone is less expensive than the L7/ENBT combo.
Looking forward to today's prices, over on the PLC Hardware website, and as an example stateside...
A brand new 1756-L75 is $20,200.00 retail price.
A brand new 1756-EN2T is $2,980.00 retail price.
That makes a combined total of $23,180.00.
A brand new 1756-L85E with embedded Ethernet is $20,300.00 retail price.
That is a saving of $2,880.00 while harnessing state-of-the-art features, if suitable to the application, after careful consideration.
Yes, do indeed take another look. You may be pleasantly surprised.
Regards,
George
