S7-315 to Honeywell PGM

Hi, I'm facing some hardware selection problem for S7.
I have a Honeywell system that will communicate with my S7-315-2 PN/DP.

S7 will have 10 profibus slaves on 1 DP network and will be a DP slave for Honeywell using S8 profibus gateway module.

As S7 cannot be master and slave at the same time, i have to select a CP, and there is a problem:

CP-342-5 can send/receive max 240 Bytes in slave mode and I need a little more (circ. 300-360).

I was thinking about DP/DP coupler - but again it can only handle 240 bytes.

What do I need on S7 side to send more ( and I cannot multiplex send data ) ?

Here's the Honeywell PGM:
https://www.honeywellprocess.com/library/support/Public/Documents/Profibus_Gateway_Module_User's_Guide_EXDOC-XX88-en-110.pdf

How time critical is your data?

You can send different data if you want, for example, use the first INT as an identifier 1 or 2.

Then on the other end of the line they look at the identifier and put the data in place accordingly.

You might be able to do generic send/recv commands (FMS or FDL) instead of Profibus, to send more data. This would probably be less deterministic, but might allow for more data. I'm not sure what is supported on the honeywell side.

As far as I know, 244 bytes of IO data is a Profibus limitation. If you want to send the data via Profibus, you would need to split the data somehow. You said you can't multiplex the data, but maybe you could use two slaves to transmit the data. This could either be 2 CP cards, 2 DP/DP couplers, etc. Technically, it could be one of each as well, but that starts getting messy.

Data is rather critical - simocode data from switchgear / commands from DCS - I'll go with 2 CPs - Thank You.