Does Seneca Z-3AO understand a function 5 code (Modbus RTU)? -
in user manual specify address's of "analog output holding registers", allows implement function codes 3, 6 , 16.
ps. want change single coil (bit) in eprflag-register (bit 12), user manual dose'nt specify data address of coil. exemple: bit 12 has coil-number 00002, gives 2-1=1 data address.
if "write coils" function not available, may still have possibility read entire register, change desired bit, , write entire register.