# Is it possible to send a value to multiple MODBUS devices at a time?

**URL:** <https://forum.inductiveautomation.com/t/is-it-possible-to-send-a-value-to-multiple-modbus-devices-at-a-time/29233>\
**Category:** Ignition\
**Created:** [October 21, 2019, 7:55am UTC](https://forum.inductiveautomation.com/t/is-it-possible-to-send-a-value-to-multiple-modbus-devices-at-a-time/29233 "2019-10-21T07:55:07Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![sac](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/sac/32/11370_2.png) [@sac](https://forum.inductiveautomation.com/u/sac)\
**Post date:** [October 21, 2019, 7:55am UTC](https://forum.inductiveautomation.com/t/is-it-possible-to-send-a-value-to-multiple-modbus-devices-at-a-time/29233/1 "2019-10-21T07:55:07Z")

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If I have 5 MODBUS devices with devices IDs 1,2,3,4 and 5. Is it possible to send a value to the same register of all 5 devices together?

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [October 21, 2019, 12:41pm UTC](https://forum.inductiveautomation.com/t/is-it-possible-to-send-a-value-to-multiple-modbus-devices-at-a-time/29233/2 "2019-10-21T12:41:47Z")

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Not in a single device transaction. The modbus protocol doesn’t have any way to address multiple devices in a single operation. The closest you can get is to pack all five writes into a single `system.opc.writeValues()` call.

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**Author:** ![jay](https://avatars.discourse-cdn.com/v4/letter/j/ed8c4c/32.png) [@jay](https://forum.inductiveautomation.com/u/jay)\
**Post date:** [October 21, 2019, 5:37pm UTC](https://forum.inductiveautomation.com/t/is-it-possible-to-send-a-value-to-multiple-modbus-devices-at-a-time/29233/3 "2019-10-21T17:37:44Z")

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In theory you can write to address 0. That’s the broadcast address. You’ll have to make sure the slaves support that. They will not respond, so your write will get a timeout even if it works.

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**Author:** ![sac](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/sac/32/11370_2.png) [@sac](https://forum.inductiveautomation.com/u/sac)\
**Post date:** [October 24, 2019, 12:36pm UTC](https://forum.inductiveautomation.com/t/is-it-possible-to-send-a-value-to-multiple-modbus-devices-at-a-time/29233/4 "2019-10-24T12:36:23Z")

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Whenever I am sending something to 0, nothing happens.