# ModbusTCP Fails with address gap **URL:** \ **Category:** Ignition\ **Created:** [October 20, 2020, 2:44pm UTC](https://forum.inductiveautomation.com/t/modbustcp-fails-with-address-gap/39834 "2020-10-20T14:44:10Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![rsonnicksen](https://avatars.discourse-cdn.com/v4/letter/r/8e8cbc/32.png) [@rsonnicksen](https://forum.inductiveautomation.com/u/rsonnicksen)\ **Post date:** [October 20, 2020, 2:44pm UTC](https://forum.inductiveautomation.com/t/modbustcp-fails-with-address-gap/39834/1 "2020-10-20T14:44:10Z")
I am running Ignition Edge V7.9.16. I have successfully created tags which read Input Registers (30000) tags, I am reading floating point variables, starting at 30011 thru, 30019. But I have a gap in addresses, and my next tag points to 30031,and when I apply this, ALL of the modbus tags fail. If I disable the 30031 tag, the other tags go back to GOOD status. - On my gateway, advanced properties are: 125 Holding Reg 125 Input Reg 2000 coils 2000 discrete inputs Rev Word: True One-based: True Span Gaps: True Allow Write Mult: True Force Multiple Reg Writes: False Allow Write Mult Coil: True Allow Read Mult Reg: True Allow Read Mult Coil: True Allow Read Mult Discrete: True Reconnect: True ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [October 20, 2020, 2:45pm UTC](https://forum.inductiveautomation.com/t/modbustcp-fails-with-address-gap/39834/2 "2020-10-20T14:45:20Z")
Disable the “Span Gaps” advanced property. ---
**Author:** ![rsonnicksen](https://avatars.discourse-cdn.com/v4/letter/r/8e8cbc/32.png) [@rsonnicksen](https://forum.inductiveautomation.com/u/rsonnicksen)\ **Post date:** [October 20, 2020, 2:51pm UTC](https://forum.inductiveautomation.com/t/modbustcp-fails-with-address-gap/39834/3 "2020-10-20T14:51:53Z")
Will that hurt my communication performance. My interface will require approx 200 floating point values and 200 coils? Will a separate request be needed for each register, or only where there is a gap? (BTW - that DID fix the problem) ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [October 20, 2020, 2:56pm UTC](https://forum.inductiveautomation.com/t/modbustcp-fails-with-address-gap/39834/4 "2020-10-20T14:56:34Z")
> [@rsonnicksen](#): > > Will that hurt my communication performance A little yes. It will result in more requests, but only results in more requests at the gaps. It does not result in every register being read in its own request unless every register is gapped from the next.