Time between char calculation on Modbus devices

In Premium and M340 PLC, Serial Modbus configuration screen allows to set delay between frames parameter (Note that this parameter called "Delay between char" in PL7 does correspond to delay between frame parameter).
On the other hand, we calculate internally delay between characters parameter. The way of calculation depends on the product you are using but also on the version of product you are using. The goal of this resolution is to provide all different calculation formulas regarding PRODUCTS and versions.
Please refer to Modbus norm (www.modbus.org) to have definitions of delay between frames and delay between characters parameter.

Note that playing with that delay between frames parameter as well as Master answer delay parameter has a direct impact on modbus network performances. Bad parameters settings can lead to communication losses.

Definitions :
TIC : Time Inter Characters
DBF : Delay Between Frames (configurable in UnityPro / PL7)

- SCP 111/114 :
* V2.x : TIC = DBF
* V3.0 : TIC = 0,5 chars
* V3.1 : TIC = 1,5 chars
* >=V3.2 : TIC = DBF - 2 chars
- SCY 21601 / 11601
* TIC = DBF
- QUANTUM :
* TIC = 3 chars
- M340 embedded port
* TIC = (3 * DBF) /7
- M340 NOM module
*TIC = DBF - 2 chars

Note that time is expressed in "char" (means time duration for one char transmission) => depends on the transmission speed (not a fixed time)