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Groups > sci.electronics.design > #453501 > unrolled thread
| Started by | David Lesher <wb8foz@panix.com> |
|---|---|
| First post | 2017-03-25 02:46 +0000 |
| Last post | 2017-03-28 14:47 +0000 |
| Articles | 6 on this page of 26 — 7 participants |
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Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-03-25 02:46 +0000
Re: Output boards, SPI vs I2C krw@notreal.com - 2017-03-24 23:25 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-03-26 04:13 +0000
Re: Output boards, SPI vs I2C rickman <gnuarm@gmail.com> - 2017-03-25 14:04 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-03-26 04:11 +0000
Re: Output boards, SPI vs I2C rickman <gnuarm@gmail.com> - 2017-03-26 02:37 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-03-26 14:41 +0000
Re: Output boards, SPI vs I2C rickman <gnuarm@gmail.com> - 2017-03-26 12:47 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-03-26 19:49 +0000
Re: Output boards, SPI vs I2C rickman <gnuarm@gmail.com> - 2017-03-27 10:49 -0400
Re: Output boards, SPI vs I2C Jasen Betts <jasen@xnet.co.nz> - 2017-03-27 18:41 +0000
Re: Output boards, SPI vs I2C Martin Riddle <martin_ridd@verizon.net> - 2017-03-27 19:07 -0400
Re: Output boards, SPI vs I2C Jasen Betts <jasen@xnet.co.nz> - 2017-03-28 08:03 +0000
Re: Output boards, SPI vs I2C Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-28 10:44 -0400
Re: Output boards, SPI vs I2C Jasen Betts <jasen@xnet.co.nz> - 2017-03-28 18:59 +0000
Re: Output boards, SPI vs I2C Martin Riddle <martin_rid@verizon.net> - 2017-03-28 15:37 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-04-03 17:49 +0000
Re: Output boards, SPI vs I2C rickman <gnuarm@gmail.com> - 2017-04-03 15:18 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-04-04 02:59 +0000
Re: Output boards, SPI vs I2C rickman <gnuarm@gmail.com> - 2017-04-04 00:54 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-03-28 05:08 +0000
Re: Output boards, SPI vs I2C rickman <gnuarm@gmail.com> - 2017-03-28 02:16 -0400
Re: Output boards, SPI vs I2C Martin Riddle <martin_ridd@verizon.net> - 2017-03-27 19:03 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-03-28 03:28 +0000
Re: Output boards, SPI vs I2C rickman <gnuarm@gmail.com> - 2017-03-28 00:38 -0400
Re: Output boards, SPI vs I2C David Lesher <wb8foz@panix.com> - 2017-03-28 14:47 +0000
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| From | David Lesher <wb8foz@panix.com> |
|---|---|
| Date | 2017-03-28 05:08 +0000 |
| Message-ID | <obcr45$6ss$1@reader1.panix.com> |
| In reply to | #453877 |
rickman <gnuarm@gmail.com> writes: >I'm no expert on PLC, but if you aren't using any of the >hardware I would suggest you get a microcontroller board >instead. There are TONs of good products that are smaller and >more cost effective. But I believe PLCs often have a special >language for programming, ladder logic. I didn't think it was >used much even for PLCs though. We don't want ladder-logic. This box was suggested by folks using them & the programmer is happy so far. Its advantages are it's already built, has most of the functionality we need in one box, and is inexpensive vs. the labor of building anything. We will be using other aspects, such as the analog inputs, RTC, and the touch screen. If you are aware of a different unit (....no matter if it's called a PLC or an X-15) that does what this one does, plus a wired Ethernet port, suggestions welcome. -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-03-28 02:16 -0400 |
| Message-ID | <obcutl$24o$1@dont-email.me> |
| In reply to | #453954 |
On 3/28/2017 1:08 AM, David Lesher wrote: > rickman <gnuarm@gmail.com> writes: > > >> I'm no expert on PLC, but if you aren't using any of the >> hardware I would suggest you get a microcontroller board >> instead. There are TONs of good products that are smaller and >> more cost effective. But I believe PLCs often have a special >> language for programming, ladder logic. I didn't think it was >> used much even for PLCs though. > > We don't want ladder-logic. This box was suggested by folks > using them & the programmer is happy so far. > > Its advantages are it's already built, has most of the > functionality we need in one box, and is inexpensive vs. the > labor of building anything. I'm not sure what "already built" means other than the obvious thing. But why wouldn't other boards be "already built"? Are you saying this comes in a box? Does that include the relay boards? If you need to put the relay boards in another box, why not put it all in one box? > We will be using other aspects, such as the analog inputs, RTC, > and the touch screen. Analog inputs are not uncommon on CPU boards along with RTC and touch screen. In fact, all this is extremely common. > If you are aware of a different unit (....no matter if it's > called a PLC or an X-15) that does what this one does, plus a > wired Ethernet port, suggestions welcome. You can get a Raspberry Pi for a number between $5 and $35 including a 40 pin header with serial, SPI and I2C ports along with 3.3 volt GP I/O. It is easy to find an analog input module to plug into the header and it is easy to find RTC and touch screen LCDs. I don't know just how the unit you are looking at is packaged. But if you are happy with it, go for it. I'm just saying that there is a lot on the PLC that you aren't using. In fact, all the stuff that you aren't using is what makes a typical PLC different from a CPU card. So it just seemed a bit out of line. But the price for this PLC is pretty good actually. My brother is using one that is a *lot* more money. -- Rick C
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| From | Martin Riddle <martin_ridd@verizon.net> |
|---|---|
| Date | 2017-03-27 19:03 -0400 |
| Message-ID | <lf6jdc9u2l0hj0r3gqcgf81i7hm0djmn0a@4ax.com> |
| In reply to | #453501 |
On Sat, 25 Mar 2017 02:46:33 +0000 (UTC), David Lesher <wb8foz@panix.com> wrote: >I pondering a microcontroller project that will need a number (say 24) >output relays. > >Is there a reason to use I2C over SPI? It looks like there are 8-channel >boards of both ilks, and I don't know if one has an advantage in this case. The OPEN PLC device does not indicate if the I2C and SPI busses are brougth out to a connector. Thus you might be forced to bit bang the OC digital outputs. Cheers
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| From | David Lesher <wb8foz@panix.com> |
|---|---|
| Date | 2017-03-28 03:28 +0000 |
| Message-ID | <obcl85$9dn$1@reader1.panix.com> |
| In reply to | #453926 |
Martin Riddle <martin_ridd@verizon.net> writes: >>Is there a reason to use I2C over SPI? It looks like there are 8-channel >>boards of both ilks, and I don't know if one has an advantage in this case. >The OPEN PLC device does not indicate if the I2C and SPI busses are >brougth out to a connector. Thus you might be forced to bit bang the >OC digital outputs. They both do, but I'm not clear if the SPI has enough enable lines. -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-03-28 00:38 -0400 |
| Message-ID | <obcp78$kgs$1@dont-email.me> |
| In reply to | #453947 |
On 3/27/2017 11:28 PM, David Lesher wrote: > Martin Riddle <martin_ridd@verizon.net> writes: > >>> Is there a reason to use I2C over SPI? It looks like there are 8-channel >>> boards of both ilks, and I don't know if one has an advantage in this case. > >> The OPEN PLC device does not indicate if the I2C and SPI busses are >> brougth out to a connector. Thus you might be forced to bit bang the >> OC digital outputs. > > They both do, but I'm not clear if the SPI has enough enable lines. The I2C port is a hardware interface on the MCU, so it will have a driver in software so that it will be easy to program. If you are happy with the I2C relay board, there is no reason to use the SPI port. You just need to set the address switches differently on each of the relay boards so that there are no address conflicts including the other I2C peripherals like the display. -- Rick C
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| From | David Lesher <wb8foz@panix.com> |
|---|---|
| Date | 2017-03-28 14:47 +0000 |
| Message-ID | <obdt2j$oqo$1@reader1.panix.com> |
| In reply to | #453953 |
rickman <gnuarm@gmail.com> writes: >The I2C port is a hardware interface on the MCU, so it will have a >driver in software so that it will be easy to program. If you are happy >with the I2C relay board, there is no reason to use the SPI port. You >just need to set the address switches differently on each of the relay >boards so that there are no address conflicts including the other I2C >peripherals like the display. I thought the display was on the SPI bus. The choice is also a function of what relay boards of each ilk I find. I expected to find lots, and have not. -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
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