Which Hardy Instrument should I use in my continuous process for rate control?

Hardy Instruments provides three rate controllers:

The HI 1756-FC is designed to plug directly into your ControlLogix PLC rack.
The HI 1769FC is also designed to plug directly into your Compact logix or Micrologix 1500 PLC. 
The HI 4060 is a stand-alone rate controller with multiple communication options, including Ethernet IP, Modbus TCP/IP, DeviceNet or Profibus, and comes standard with four channel analog output. 

These three controllers were based from our former product HI 2160RCplus weight controller, with many control improvements and general ease of operations.