# Add delay between Polls for devices in Modbus RTU

**URL:** <https://forum.inductiveautomation.com/t/add-delay-between-polls-for-devices-in-modbus-rtu/40591>\
**Category:** Ignition\
**Created:** [November 12, 2020, 5:01pm UTC](https://forum.inductiveautomation.com/t/add-delay-between-polls-for-devices-in-modbus-rtu/40591 "2020-11-12T17:01:49Z")\
**Posts on this page:** 1\
**Showing post:** 6

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**Author:** ![nader.chinichian](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nader.chinichian/32/9261_2.png) [@nader.chinichian](https://forum.inductiveautomation.com/u/nader.chinichian)\
**Post date:** [November 13, 2020, 2:29pm UTC](https://forum.inductiveautomation.com/t/add-delay-between-polls-for-devices-in-modbus-rtu/40591/6 "2020-11-13T14:29:33Z")

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Unfortunately I notice today that driver issue all poll request at the same time for all IDs in the bus. So every device try to answer the request base on their ID and we have collisions detection on the RS485 bus. It seems the one who write the driver think it works as TCP connection and doesn’t care about serial limitation.  
I hope IA fix this issue unless the driver is totally useless in serial mode.  
Using system.opc.read is fix the problem and it’s good for small tag count but it ruin rapid development concept here. Even using external modbus TCP TO SERIAL doesn’t solve the problem here.

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