ModbusTCP Fails with address gap

Ignition
1

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

2

Disable the “Span Gaps” advanced property.

1 Like
3

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)

4

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.