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| 2/1/2012 3:14 PM | |
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Posts: 2 Rating:
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Dear All, I have a question regarding SIEMENS DI card (particularly SM421 - 6ES7 421-1BL01-0AA0). I’ve searched already the forum but didn’t find any specific answer to my problem. I would like to connect a SJ3,5-G-N Inductive sensor (NAMUR) from Pepperl+Fuchs to this card without using some extra switch amplifier. The sensor is in non-hazardous area (no Ex-Zone - no need for intrinsically safe connection) and it won’t be used for Safety application. According to the sensor’s datasheet: Switching element function NAMUR, NC Nominal voltage Uo 8.2 V (Ri approx. 1 kO) Operating voltage UB 5 ... 25 V Current consumption Measuring plate not detected >= 3 mA Measuring plate detected <= 1 mA In the the specification of the card for 2-wire BERO sensors (page 110 from SIMATIC S7-400 S7-400 Automation System Module Data) I’ve found: “As long as the current flowing into the module remains <= 1.5 mA, the module recognizes this as a "0" signal.” My question is if it will be possible to connect directly the 2-wire NAMUR sensor on 24VDC with the SM421 card? Best regards… AttachmentSM421 S7-400 Automation System Module Data.pdf (245 Downloads) |
| 2/2/2012 11:21 AM | |
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Posts: 21 Rating:
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Hi printf, So, I read the manuals of the sensor and the mudule and not found no problem in using both. As the sensor with measuring plate not detected I>= 3mA and measuring plate detectedI <= 1mA, the module assumes the state "0" with I <= 1.5mA. Did you make same tests? Best Regards! Marciel Fernandes Academic of Control and Automation |
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