I honestly had no idea, but I was on my way back to my home office so I told him I would look it up and get back to him.
What I found in my research was, when compared to typical the DC input modules like the 1769-IQ16, the 1769-L1's built-in I/O was indeed faster. To illustrate this comparison I have pasted the specs of both below:
1769-IQ16 Input Speed Specs:
1769-L1xER Embedded Input Speed Specs:
As you can see above, while the 1769-IQ16 has an on / off delay time of 8ms (what I would consider typical,) the 1769-L1 embedded I/O has a much faster 0.5ms on / off delay time – the same as 1734 point I/O modules like the 1734-IB4.
However, this isn't the whole story. While I/O delay time is important, with the CompactLogix and ControlLogix we must also consider if the I/O supports event based tasks, as well as the maximum supported RPI setting.
Dropping the 1769-L1 into RSLogix5000 v20 it quickly became apparent the embedded I/O can not trigger an event based task, as seen in the below screen shot:
The final consideration was to find the fastest RPI supported by the L1's embedded I/O. While RSLogix5000 v20 does support a setting of 1ms RPI for the embedded I/O, the below excerpt from the L1 Tech Data sheet reveals that the true limitation is based on the number of modules (including embedded) in a system:
In summary, the 1769-L1 family of CompactLogix processor's embedded I/O contains the same .5ms on / off delay times as many 1734 Point I/O modules of the same type. And while this is considerably faster than standard I/O modules, like the 1769-IQ16 with it's 8ms on / off delay, the speed advantage is quickly lost as you add more I/O modules to the 1769-L1 base system (with a full 8 module system limited to a maximum RPI of 8ms.)
Note: For more details on the 1769-L1 see the Allen-Bradley 1769-TD005 Technical Data Sheet here.
I hope this review of the speed of the embedded DC inputs on the 1769-L1 has been helpful. If you have any comments or questions please don't hesitate to leave them by using the “post a comment or question” link below.
Enjoy the benifits of membership! Insider news, rewards, & more: Patreon.com/automation
If you enjoyed my article, you may like my courses at TheAutomationSchool.com
Have a question on this topic? Click here to scroll down to the comment link
Have a news tip? Share it with us here
Latest posts by Shawn Tierney (see all)
- Automate In Style: Check Out Our New T-Shirts! - February 18, 2020
- PanelView Plus to ControlLogix, SLC-5/04, & PLC-5 over DH Plus (Early Access) - February 17, 2020
- PanelView Standard to CompactLogix or ControlLogix over DH Plus or DH-485 (Video, S33) - February 14, 2020
Click HERE to scroll down to view or leave comments