Serial communications from Redundant RTUs

[michael_mckay_p]

I would like to connect a daisy chain of 6 ModbusRTU devices on an RS-485 network to a pair of redundant Saitel DR HUe RTUs. As ModbusRTU is a master slave network is this possible? Will only one of the Saitel DRs attempt to control the RS-485 network at any one time? And so will the other take over if the primary fails?

Thanks for your thoughts

[Iván_González · Accepted solution]

Hi Michael,

Althoug redundancy in Saitel DR is a bit limited in comparison to Saitel DP, waht ou are proposing is certainly feasible. The Saitel redundancy mechanism is very robust and designed to manage syustems exactly as you  point at: HOT-STANDBY ssytems where only one CPU (the HOT one) is actively exchanging data with the field, while the STANDBY one gets database updates from it.

From an external point of view, if adequately configured, it is a single system both upstream and downstream.