Are the option cards the same for the HI 2151/20WC, HI 2110WI, and the HI 2151/30WC?

All option cards except the serial communications option cards from the HI 2151/20WC can be used in the HI 2151/30WC and the HI 2110WI. The RS232, RS485, and RS422 serial communication options are standard in the HI 2151/30WC and made available using the basic serial port P1. The serial option cards used on the HI 2151/20WC controllers will not function in the HI 2151/30WC or the HI 2110WI.

Modbus communications support is not available or supported on the HI 2151/30WC.

There were older option cards for HI 2151/WC that are not compatible or usable in the HI 2151/20WC or the HI 2151/30WC. These circuit board part numbers start with number 0535-03xx. These 0300 series cards have the incorrect pin configuration and will damage the HI 2151/20WC and HI 2151/30WC models.