If you are using the HC900 Modbus Slave Function Block (FB), then the HC900 is the Modbus Master/client who reads from the E&H recorder which is a Slave/server using the MBS and MBR Function Blocks.
Assuming you want to read the values from the recorder, then each RDn position on the right side of MBS1xx FB or the MBR1xx Modbus Read FB must be "tagged" with a tag name and the tag configured to read register nnnnn (hexadecimal addressing, zero based) and have the correct Function code associated with the register in the recorder, as shown in the screen shot of the properties of the MBR FB.
In the attached file, Slide #22 (page 1, bottom, pdf) "Modbus Master Interface - Serial" summarizes the Modbus master function, which is the same for Ethernet/TCP as it is for serial, other than the serial configuration required on the HC900 COM port. Yes, I know you're doing Ethernet, but the setup of the Modbus functions are the same, only the COM port varies. Obviously, the register addressing is different for the E&H than it is for the Honeywell in the example.
Assuming you want to read the values from the recorder, then each RDn position on the right side of MBS1xx FB or the MBR1xx Modbus Read FB must be "tagged" with a tag name and the tag configured to read register nnnnn (hexadecimal addressing, zero based) and have the correct Function code associated with the register in the recorder, as shown in the screen shot of the properties of the MBR FB.
I always word at getting just one or two points read and displayed before moving onto all the configuration for the remaining points.