Freelance time synchronisation using NTP
Freelance offers time synchronisation from external references using the serial port of AC 800F controllers, e.g. from DCF77 or NAVSTAR-GPS signals.
If you had no signal reception at the site, but an intranet with a working NTP server, could you set up Freelance to synchronise to it?
I've read 3BDD011812-600 (800xA for Freelance configuration; 800xA be neglected here) where they describe how to use 800xA connectivity servers over OPC as time master for Freelance. The instructions are a bit meagre though (p. 91):
The time of the connectivity server is distributed through OPC-Server to the controller. The configuration has to be done in Freelance Control Builder.
1. Open the Config window on OPC-Gateway station.
2. Enable the Ext. time server checkbox.
3. Configure the IP addresses.
Three controller [sic] can be connected. In case the first one fails the next one takes over.
From this I suppose that in those fields you enter external time servers (800xA Connectivity servers?) that pass the current time to Freelance.
But the documentation 3BDD012503R0801 (Freelance Engineering Manual, System Configuration) says on p. 129 under "External timer server":
In Freelance system, all stations are time-synchronized by the first PS or by an electronic timer (radio controlled clock).
External stations that are connected by means of a router or modem can be time-synchronized by the operator station PC, a gateway PC, or a DCP gateway. For this purpose, the "Ext. Timer Server" [sic] function must be activated in the resource configuration [...]. By specifying the IP address, up to three stations can be time synchronized by a resource.
From this excerpt, I understand that the gateway imposes its time upon other stations configured in the "Ext. timer server" function.
The first fragment however makes me assume the OPC gateway draws the time from stations entered in the "Ext. time server" fields to distribute it between Freelance stations.
Which perspective is correct (or is there an error in my understanding)? Can I use this function to hook up Freelance to an NTP server? Are there other possibilities for synchronising Freelance to an external time reference?
Thanks and best regards
Voted best answer
To use NTP server simply:
1. Disable Freelance Time synchronisation in Settings of Freelance OPC Server PC.
2. Set up NTP time synchronization on this OPC Server PC (with standard Windows settings).
3. Go to Freelance Engineering/CBF and in header of OPC Server resource input IP adress of Freelance Controller (or multiple addresses, if You want) under "Ext. timer server".
4. Load changes
How does this work?
You sync the NTP time to OPC Server PC which passes it to controllers defined under "Ext. timer server". Then, according to standard Freelance procedure, the Controller synchronizes the Freelance stations on the same network. You need to exclude the OPC Server from synchronisation, as it would create a loop of time sync.
Hope this helps,