9/23/2014 10:39 AM | |
Joined: 12/1/2009 Last visit: 6/7/2024 Posts: 672 Rating:
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Dear Dert, if you use CM1241 with RS485 interface you should be able to connect all your load cells in multidrop-network to your CM. The RS232 at your load cell devices you can simply convert to RS485 with converters. RS232 interfaces are usually for Point-to-Point connections between two devices. What protocolare youusing? Best Regards. |
Last edited by: TIBI68 at: 9/23/2014 10:42 AMGive us your feedback and show us your respect! |
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9/23/2014 11:05 AM | |
Posts: 1058 Rating:
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Hello Dert, RS 232 has been designed as point to point connection and does not really fit to multiplexing. Although it might be technically possible to do so, there are easier ways build a network. RS 422 and RS 485 have been designed for more than one nodes. So easiest way to build a network with RS 232 is just as TIBI68 already stated: convert your RS232 to RS485. You should even be able to use same protocol, as long as there is no hardware handshake for your RS232. You will find a typical RS232 to RS485 converter here. But there are of course many on the market. Regards |
9/23/2014 12:49 PM | |
Joined: 12/1/2009 Last visit: 6/7/2024 Posts: 672 Rating:
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Hi Dert, that's why I was asking about the protocol. TheASCII frame you receive must contain a unique device ID number in order to distinguish between the individual devices, otherwise it does not work. Maybe you can find something about in the manual of your load cell device. Best Regards. |
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9/23/2014 3:43 PM | |
Joined: 7/7/2010 Last visit: 8/28/2024 Posts: 15116 Rating:
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Here's what Blackbox Offers at a pretty high price with guaranteed lifetime support. For the price you may be able to get a small s7-1200 and rs232 module and handle that 4th load cell. It might be less expensive to look for a different load cell transmitter, or an option board that converts to rs485 right on each load cell's transmitter. |
science guy |
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9/25/2014 7:33 AM | |
Posts: 15 Rating:
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I am intended to buy a ET200SP IM and plug the 4. RS232 module on the IM. That would also work, wouldn't it? |
9/25/2014 7:49 AM | |
Joined: 12/1/2009 Last visit: 6/7/2024 Posts: 672 Rating:
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Sorry Dert, but S7-1200 does not work with it, S7-1500 does (SIEMENS Logic) Check from here: Does your load cell device not provide an ID number in the protocol? Best Regards. |
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9/25/2014 8:01 AM | |||
Joined: 12/1/2009 Last visit: 6/7/2024 Posts: 672 Rating:
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Just a stupid question Dert , why do you not just simply get a CB1241 (RS485) and connect your 4th device to itthrough aRS485/RS232converter ? Best Regards. |
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Last edited by: TIBI68 at: 9/25/2014 8:09 AMLast edited by: TIBI68 at: 9/25/2014 8:03 AMGive us your feedback and show us your respect! |
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9/25/2014 8:34 AM | |
Posts: 15 Rating:
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Because i didn't know that such a module exists :). I think this is the best solution. Thank you. |
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