RS485 connection delay

Hello All,

I have 3 Schneider ION power analyzers, I'm connecting them as a chain to Advantech ECU 1251 gateway to convert to ethernet, then it connected to SCADA system, it was noticed that there is 2 seconds delay between the SCADA reading and the ION HMI reading, is it normal delay ? can it being improved ? knowing that the devices located in the same room.
No, it is not expected for there to be that long of a delay for a RS-485 to Ethernet gateway. There is likely a configuration setting that needs to be modified. Here are some additional details, for context.

There are two types of protocol converters: routers and gateways.

A router simply translates each request and response, on-the-fly, between two networks (typically using the same protocol, such as Modbus/TCP to Modbus RTU). This translation will introduce some delay, as the router must receive the entire request, translate the request, transmit a new request onto the other network, receive the entire response, translate the response, and transmit the response back to the original sender. Configuration of a router is much simpler than a gateway, and typically only consists of configuring the communication settings for each network.

A gateway, on the other hand, services all request immediately from its internal database (data cache). A gateway device will constantly synchronize its internal database with the target devices, mirroring their data in its internal database. Configuration of a gateway is more complex than a router because in addition to configuring the communication settings for each network, you must also map objects/registers that the gateway will synchronize and expose to the other network.

I was unable to find any details online regarding the configuration of the Advantech ECU-1251, so I can't provide specifics, but this device is probably a gateway. Therefore, there should be some setting which controls that rate at which the ECU-1251 synchronizes data with the ION power meters (something similar to Scan Rate, Poll Rate, Request Delay, etc.).