Strasis Systems supports Modbus TCP (via the Modbus driver) and has employed the AutomationDirect PLCs for extensive testing.  These low cost programmable controllers offer a very high value and are easy to deploy. BRX series controllers provide Industrial IoT Integration, data logging, motion control, high speed I/O and processing power, with customizable communications, to meet the changing demands of industrial automation projects. 

AutomationDirect: https://www.automationdirect.com

BRX Programmable Controllers: https://www.automationdirect.com/do-more/brx