Modbus Settings Registers starting at 00121 control the IOFEPs outputs, command switch positions and protection switch modes.
Register Purpose Remarks
00121 outputs 1..16 The lsb in this word controls
output 1, the msb output 16
00122 outputs 17..32 Reserved for future use
00123 wg switch 1..8 See 'WG Switch Actuation' below
commands
...
00126 wgswitch 29..32
commands
00127 protection switch 1 See 'Protection Switch Control'
command below
...
00158 protection switch 32
command
WG Switch Actuation
Commands for WG switch actuation are encoded in two bits per switch, the least significant two bits for switch 1. A bit combination '01' commands position 'A', '10' commands position 'B'. The combinations '00' and '11' are ignored, the switch position remains unchanged. If multiple switch movements are commanded at the same time, the switches move contemporaneously unless the number of parallel switch actuations has been limited in the setup.
A computer controlling the IO-FEP2 may use the actuation registers like it would control the actuation motors directly: switching on a motor and switching it off a few hundred milliseconds later. This is for compatibility with software that expects a dumb switching unit to control the waveguide switches. In fact there are no timing constraints with writing to these registers, the IO-FEP2 controls the actuation timing off the switches internally.
Controlling wave guide switches which either are not configured or not licensed at all, has no effect.
Protection Switch Control
There is one control register for each protection switch unit. These registers are 'command-only', reading them back always returns 0.
For each protection switch the following commands are defined:
0 NOP, do not change the protection switch
1 Set the protection switch to UNUSED
2 Set the protection switch to 1:1-SW-ONCE
3 Set the protection switch to 1:1-SW-ALWAYS
4 Set the protection switch to DISABLED
5 Set the protection switch to ENABLED
6 Set the protection switch to position A
7 Set the protection switch to position B
8 Reset the SWITCHED flag of the protection switch
9 Set the protection switch to SW-2TO1
Protection switch commands 1..5 and 9 alter the protection switch setup data, cause the setup.txt file to be written to sd-card.