Hi,

Just want to confirm if is it possible to add a modbus connection to a Hot Standby configuration (Quantum) with existing Remote I/O drops. The CPU Module is 140 CPU 67 160. I also used a Ethernet Module (NOE 771 01) for the network communication.

The specs say that I should connect the CRAC Units via modbus cable to the CPU's.

Is it possible since the CPU module has a modbus port? If yes, do I still need other modules (specifically for modbus connection) ?

Hope that someone can help me.

sure you can. You have an integrated modbus port. You could even configure the switchover of the addresses if the cpu swapped to the other.

Correct me if I am wrong, will I use a splitter (for MODBUS) to be able to connect it on both primary and standby CPU?

The modbus port master could have addresses from 1 to 119, automatically the modbus port standby will have address master+128.
ie

mb master = 1
mb standby = 129

So both ports could be connected to the same serial bus because their addresses are managed by the hot-standby system.
You can use any modbus equipment but remember that the integrated CPU modbus port are RS232C so you need to configure previously in rs485.

I don't know what you mean with "splitter", you have to create a multi-drop 485 bus.

you could use i.e. the SCA62 and two cables VW3A8306 for connecting the quantum cpu's

Modbus is an RS-232 serial comm link. You cannot "parallel" the connections.
They must be isolated with a modem of some type.
As mentioned the address' will (if selected to) be offset by 128.

That's true for all Quantum CPU's but the HSBY one.
I can't verify cause I don't have a CPU HSBY, but I see in the user manual that the Modbus Port 1 is configurable RS232 or RS485. In effect in Unity such a configuration is possible..

See the attachment withdrawn from the User Manual 35010533 November 2007.



Just in case (see above) you have to convert your electrical signal from RS232 to RS485 link with for example the XGSZ24 RS232/485 converter (just to stay in Schneider house) or others