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How to Increase I/O in S7-2xx CPUs

Created by: Jamil_paki at: 8/5/2008 8:20 AM (11 Replies)

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8/5/2008 8:20 AM	Rate (0)
Jamil_paki Posts: 22 Rating: (0)	Is there a Way to STAY IN S7-2xx environment and Have More I/Os than allowed after expansion modules. For instance is it possible to Have a S7-226, with Maximum I/O modules linked to 1 or more S7-226 with Maximum I/O modules. just for your info. No complexe programming, just require Lots of On/Off Switches and Indicators to blink ina Big plant. Lastly, What hardware would be required? Any Pros/Cons?
Jamil_paki Posts: 22 Rating: (0)
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8/5/2008 10:19 AM	Rate (0)
neo Posts: 264 Rating: (59)	Hello! I don´t think you´re ableto have more I/O´s than allowed. But perhaps you can handle it different. You could use a Ethernet-CP243-1 for your CPU226 second CPU (eg CPU224) and a CP243-1 too. So you are able to communicate between these Stations, and use the second CPU just as an I/O Station. Further have a look at the ASI-Extension module. I don´t know, but perhaps you can get mor I/O´s with ASI?! best regards...
neo Posts: 264 Rating: (59)
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8/5/2008 10:46 AM	Rate (0)
GerardAmmerlaan Posts: 60 Rating: (1)	neo Hello! I don´t think you´re ableto have more I/O´s than allowed. But perhaps you can handle it different. You could use a Ethernet-CP243-1 for your CPU226 second CPU (eg CPU224) and a CP243-1 too. So you are able to communicate between these Stations, and use the second CPU just as an I/O Station. Further have a look at the ASI-Extension module. I don´t know, but perhaps you can get mor I/O´s with ASI?! best regards... Hello, If you use a second PLC as I/O link, please note that the I/O is not read in in a deterministic manner. It could work, if non deterministic behaviour is no problem to you (slow reaction time). In this case you could even use the on board PPI port to send the I/O to the other CPU. If this is no option, I suggest investing in an S7-300. Best regards, guppy
GerardAmmerlaan Posts: 60 Rating: (1)
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8/19/2008 11:17 PM	Rate (0)
marcsinclair Posts: 49 Rating: (5)	Hi, I am suprised no-one has suggested multiplexing. You can design a matrix of your switches with eight outputs and eight inputs, then sequence the outputs on, one at a time and read the inputs, this way you can have 64 inputs for an 8IO unit. Regards
marcsinclair Posts: 49 Rating: (5)
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8/21/2008 5:27 AM	Rate (0)
Jamil_paki Posts: 22 Rating: (0)	marcsinclair Hi, I am suprised no-one has suggested multiplexing. You can design a matrix of your switches with eight outputs and eight inputs, then sequence the outputs on, one at a time and read the inputs, this way you can have 64 inputs for an 8IO unit. Regards Thanks Marc, But is it used (acceptable) or preffered to use in a commerical project? What do you about the intermidiatery device to use? design yourself or is thier a Multiplexing device to use with PLCS? I've read about Multiplexers but am notsort of clear? My confusion is that for instance there are 64 equipment (inputs/outputs) to be monitor/controlled. any one can be turned On or OFF at a time, irrespective of other equipment's status. let me draw a small chart to show what I mean. 0000 = all equipment off 0001 - eq. 1 ON 0010 - eq 1 and 2 ON?? am I correct so far 0011 - OK so here it starts getting tough for me? WHATS THIS? and what would be the status of the BYTE if only equipment #2 is turned on? got any simple link on Multiplex to clear the concept?
Jamil_paki Posts: 22 Rating: (0)
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8/27/2008 3:00 PM	Rate (0)
marcsinclair Posts: 49 Rating: (5)	Hi, Multiplexing is a perfectly acceptable strategy, look down at your PC keyboard, do you think that each key has its own input? I've just tried this out on a 222 that I have (only has 6 outputs, but you'll get the idea) I used the outputs q0.0 to q0.5 to supply six rows of a matrix, and connected the input byte (I0.0 to I0.7) to eight columns down the matrix. I then connected switches across some of the intersections. Each switch or button element will need a 1N4001 diode (0.1p each!) in series with it, to ensure that the LOW rows are not taken high by other switches in the column. Attached are screenshots from the program. The top screenshot shows the network which initialises the output byte, the multiplex timing and the interrupt setup. The next screenshot shows the interrupt routine where I ROL the output byte (it's not changed until the end of the scan), read the inputs, and transfer them to the outputs The last screenshot shows the status of the virtual inputs, and as you can see, two switches are closed With the values shown for SMB34 (Time_0_Intrvl) scanned all 48 inputs in less than a second reliably (64 would take the same time). Marc Sinclair http://s7-200.germainesystems.eu Attachment screenshots.jpg (217 Downloads)
marcsinclair Posts: 49 Rating: (5)	Last edited by: marcsinclair at: 8/27/2008 10:40 PM Clarified my explanation a bit (I hope!) I'm really bad with run-on sentences.
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9/11/2008 2:22 PM	Rate (0)
Ayman Elotaify Platinum Expert Joined: 5/28/2008 Last visit: 11/6/2024 Posts: 4516 Rating: (839)	From HW config. The CPU226 can handle up to 7 Expansion modules. Extension ofI/Os: Analog Inputs/Outputs: 35; max. 28 input & 7 output (EMs) or max. 0 Input and 14 output (EMs) Digital Inputs/Outputs: 148; max 128 input and 120 output (CPU+EMs) How many Inputs/Outputs you wan to cover by your system?
	Ayman Elotaify
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9/17/2008 5:38 AM	Rate (0)
Jamil_paki Posts: 22 Rating: (0)	Scenario, we have a couple of production lines running, and some not running at times, and some downstream running in case any line runs, (In case most users may get confused, the I/Os consist of Machine START, STOP, Saftey o/Load, Few buzzers/sirens, indicators/flashers, no fancy HSC, or analog values) I was browsing and realised I can accomplish this in another way, to achieve more I/Os and remain in the S7-200 environment (cost effective) production Line 1 = S7-2xx CPU + 6 I/O Expansion + Ethernet /IT module production Line2 = S7-2xx CPU + 6 I/O Expansion + Ethernet /IT module production Line3 = S7-2xx CPU + 6 I/O Expansion + Ethernet /IT module and another CPU S7-2xx + ethernet/IT module for the downstream equipment since the downstream equipment does not consist of many I/O, but its control is prefered from this source, we intend to place an HMI and control all previous lines and the downstream equip. from here, using the S7-2xx communicating thru the ethernet/IT module, and connected to the HMI. All the previous lines will/can be started, stopped, monitored from the production lines main CONTROL PANEL and/or last Station (downstream), comments? 1 more reason to select S7-2xx, the customer is confident with S7-2xx series, the deployment will be done in phases, thus more economical.
Jamil_paki Posts: 22 Rating: (0)	Last edited by: Jamil_paki at: 9/17/2008 5:40 AM
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9/22/2008 1:50 AM	Rate (0)
marcsinclair Posts: 49 Rating: (5)	A few questions : How do you intend to communicate between PLCs ? Why have you specified the IT versions ? What sort of HMI are you specifying?
marcsinclair Posts: 49 Rating: (5)
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9/29/2008 5:37 AM	Rate (0)
Jamil_paki Posts: 22 Rating: (0)	following lines are included in the whole plant, FINAL section (several sub-sections) Type A section Type B section Type C section 1) considering above 4 sections are running in a plant, in such a scenario that any single, or more lines can operate individually. So what I have in mind is to program a separate CPU for each section. however, the FINAL section would have the ability to control subsection aswell. that is why I was thinking to link all these 4 CPUs through the Ethernet module. 2) IT module can be installed on the Final Section CPU, to provide control/monitoring externally of this environment. 3) A simple HMI (Touchscreen) installed with each CPU seems to be sufficient.
Jamil_paki Posts: 22 Rating: (0)	Last edited by: Jamil_paki at: 9/29/2008 5:38 AM
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