Hi, Please suggest on this off-topic question. I went to nearby automation distributor.Just asked price of few basic PLC models. And was shocked. Allen Bradley...
8237
John cliffer
john17135@...
May 24, 2012 12:42 pm
Hi, Thanks for reply. Was on road so not able to reply. Will go through it before any comment. // John On Wed, May 23, 2012 at 10:54 PM, Corey, Richard < ... ...
8238
John cliffer
john17135@...
May 24, 2012 12:51 pm
# Or these PLC are more robust than our simple small micro controller based CARD As far as i know, PLC are more reliable in realtime Enviroment. Cheers, //John...
8239
Xiaofan Chen
xiaofanc@...
May 24, 2012 1:20 pm
... That is just a small part of the advantages of PLC. There are many other advantages of PLC versus custom made solution. Please also take note that Nano and...
8240
Dinesh Guleria
din.gulu.er@...
May 24, 2012 3:44 pm
... Do not agree with this point. Even with good quality Hardware design & micro-controller we can design Effective small DCS. Even automotive industry is...
8241
Geoff Field
geoff_field2003@...
May 25, 2012 12:54 am
Some good points have been raised in this discussion (even though it is off-topic for the CAN list). Some (many) of these points apply to the build-or-buy...
8242
Rufus V. Smith
rufuss@...
May 25, 2012 3:53 pm
Great advice Geoff! (saved me the trouble of saying it, and was better said.) Designing your own short run circuit board will never be the ...
8243
John cliffer
john17135@...
Jun 1, 2012 1:12 pm
Hi Everyone, I am gone through AN1798 application note from freescale for many a time now. I am able to get what all calculation is done out there in this doc....
8244
From: London Olympic ...
scanner@...
Jun 2, 2012 9:19 am
Kindly view the attached file for more information....
8245
Dinesh Guleria
din.gulu.er@...
Jun 4, 2012 12:50 pm
... edge & early bit w.r.t parameter RJW. This will be done by the silicon in CAN controller. Being an Embedded developer we only have to put right value in...
8246
Dinesh Guleria
din.gulu.er@...
Jun 4, 2012 12:50 pm
Hi , If we are using 100 ohm termination ---- then also can we use ---- 4.7nf capacitance --- with split termination --- for CAT-5 cable .. ? Or we have to...
8247
Dinesh Guleria
din.gulu.er@...
Jun 5, 2012 1:46 pm
Hello , As per slla270 application note from TI :----- ... dB point at 1.1 Mbps. Cut-off Frequency = f = 1 / 2*Pi*R*C R = 60 Pi = 3.14 C = 4.7 nF This gives...
8248
Dave Tweed
can@...
Jun 5, 2012 2:26 pm
... You need to be sure you understand the relationship between "bps" and "Hz". Alternating ones and zeros at 1.1 Mbps is a square wave at 550 kHz. So the ...
8249
John Dammeyer
johnd@...
Jun 5, 2012 3:50 pm
Hi Dave, Good reply. Steve Corrigan would be proud! He'd probably also refer to Section 4.12 of his application and comment on using 100R for bus termination....
8250
Steinhoff
steinhoff@...
Jun 5, 2012 4:01 pm
... This formula is correct for a simple RC filter (low pass) IMHO, it doesn't fit to the split termination filter ... ... Yes, at least that statement is very...
8251
Steinhoff
steinhoff@...
Jun 5, 2012 8:41 pm
... Yes, at least for the relationship of Mb/s and frequency. ... Why should it be so when a line with a line impedance of 100 ohm has been terminated with a...
8252
Dinesh Guleria
din.gulu.er@...
Jun 6, 2012 4:08 am
Thanks Dave, got the point ... on using 100R for bus termination. Hi John what is this *Section 4.12 of his application ?* * * Regards, Dinesh...
8253
John Dammeyer
johnd@...
Jun 6, 2012 5:21 am
slla270 application note from TI :----- Sorry forgot the word 'note'. The late Steve Corrigan wrote that application note. "ELS! The Solution" Automation...
8254
Dinesh Guleria
din.gulu.er@...
Jun 6, 2012 5:41 am
Thanks, yes i use to refer this App note from this only i was able to get the formula & concept of 4.7 nf capacitance used. But one thing i missed that two...
8255
isto.virtanen@...
Jun 6, 2012 6:10 am
Hello, sorry to disturb the intense discussion on the split termination and the calculation formulas, but who really needs it? In theory it is better yes, but...
8256
heikki.saha@...
Jun 6, 2012 7:09 am
Hello, Excellent comment. The split-terminator performs many functions: 1: 120R end termination of the transmission line (2x 60R) 2: Low-pass filter for the...
8257
David Harris
dpharris@...
Jun 6, 2012 7:23 am
Good question. It is theoretically better in some aspects, but may cause other problems. It is intimately related to how one handles grounding, and isolation...
8258
Steinhoff
steinhoff@...
Jun 6, 2012 8:32 am
... Oh sorry, that was not my intention. ... But we don't have a plain DC environment. At a bit rate of 1Mb/s the lowest frequence is 500kHz ... the slow rate...
8259
Dinesh Guleria
din.gulu.er@...
Jun 6, 2012 8:52 am
I will be using HVD255 ... Putting 3.1V across 50 Ohms (two 100 Ohm in parallel) is 62mA. Worst case for the recommended 120 Ohms in parallel is 52mA. Worst...
8260
Dinesh Guleria
din.gulu.er@...
Jun 6, 2012 9:18 am
I my last mail I have asked a question as per this, point raised in this mail list, which says worst case recommended in 52 mA :--- ... Page #3 of the...
Armin, I'll start off again by asking a question then. How do you think they came up with 120 nodes maximum? Why not 500 nodes? Why not 1000 nodes? The...
8263
John Dammeyer
johnd@...
Jun 6, 2012 5:15 pm
The short circuit capabilities of the drivers are much higher than 50mA. Note the word recommended. 'Typical' output voltage is 2V resulting in 33mA for the...
8264
Steinhoff
steinhoff@...
Jun 6, 2012 7:08 pm
John, ... That's excactly what I said ... ... These termination resistors have exactly the value of the wave impedance of the cable in order to minimize signal...
8265
raj katoch
katochd46@...
Jun 7, 2012 4:09 am
Hello, I have read document's of CAN & found that it is used in Automation & Vehical network. Also in automation we mostly use PLC, where we find the need that...
