AC800M Time synch
AC800M is a subsystem in a plant , AC800M Controll will get a pulse from the DCS system to set the time at 11:00 morning.How we can set the controller time, using logic functions. Then sync the HMI's.
2) If DCS is sending the time through modbus register, can we set the time in the AC800M controller.
SetDT Block is available in AC800M , can we use this block. Will it cause any issue to system performance if DCS system malfunctions.
You should understand that both of proposed methods are not the best, but still you could use them if other is not possible.
For 1) I think it could be realized with R_Trig for the pulse => use SetDT block for one cycle with a fixed time set 11:00:00... as follows:
Of course, you have to read first the current date from the controller and the to write the only fixed time - a few conversations are necessary.
May be easier is to use the relative time (read in help for SetDT):
The relative time is set as a time difference in time format, for example, 5m (5 minutes) if you want to add time, and -5m if you want to subtract time.
The AC800M should be set as clock master, then you easy can synchronize the ABB HMI - it works automatically and you need only a few settings.
For 2) may be you will need more code to write - to check if communication to external DCS is OK when reading the time (resp. this will ensure you set the correct time in AC800M), then to define some time period for writing a time in AC800M - may be once per hour.
Principally I used this method in oposite - to synchronize AC500 time to the time of AC800M.