3/30/2020 7:52 PM | |
Joined: 12/9/2010 Last visit: 10/8/2022 Posts: 623 Rating: (77) |
Hi smiffy, Great document really !! My concern is about Modbus RTU-RS485. There is very general architecture of 4-5 slave & PLC as master. The system gets hang.
1. The PLC master stops polling. Done/error bit does not update & hence no further requests 2. The done/error bit is healthy but the information is not updated. This happens with all systems e.g. 300/400/200/1510PN etc. Probable remedies were- 1. Use profibus cable 2. Proper instrument earth. Power earth isolation. etc Serious issue is that there is no alarm displayed for hung network status. User is not aware of it most of the times. There is nothing in diagnostics log of CPU/module. How to track such condition ? Sometimes the data is critical hence how to restart the polling correctly ? Any other hardware/wiring related considerations ? Reply will be appreciated. ------------------------------------------------------------------------------------------ |
Last edited by: Jen_Moderator at: 03/31/2020 10:42:56New subject after splitting If you like the comment, rate it (right top) or thank it (left bottom). |
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