How do I control a remote display with a HI 2151/30WC?

I am trying to control a remote display using a HI 2151/30WC and I cannot get it to communicate properly. I have the serial port configured as follows:

Sercon: Print
Sertyp: RS-232
Baud: 9600
Frame: 8-N-1
Format: G-----

I have matched these up with the remote display and have wired it as follows:
Hardy Txd ------ RLWS Rxd
Hardy Gnd ------ RLWS Gnd

What am I doing wrong?

To test the HI 2151/30WC serial communications setup you can stream the data from the serial port to your host communications package. This will verify you have the correct wiring, and the comm. port is good. Then work on the serial driver application program and serial commands.

In this example the communication cable is attached to COM port 1 using the standard Hyper-terminal setup on a PC. Verify the port configuration setups are identical.

Setup; baud 19,200, 8-N-1, Control = Hardware, RS232, Echo = OFF, Address 00, Sercon = print

Set format, in the weight controller under serial port P1 options, to all on except the first, P, location to blank. (Continuous output) GNTRS_ Press enter to write the format record.

Voltage checks;
Signal ground to CTS = +10 volts, when hooked to the COM 1, RTS pin seven, and communications is active. Read -6v when no communications is started or established.
Signal ground to TXD is +10volts when communications is active and -6 volt when no communications is started.
CTS held to positive voltage above 5 volts and less than 15 volts. You can use a 9-volt battery or hook to RTS on the host COM port.

Hardy 5 pin connector to 9-pin female D-shell connector for RS 232 serial communications.
Hardy RXD pin 3 to COM 1 pin 3 TXD
Hardy TXD pin 4 to COM 1 pin 2 RXD
Hardy CTS pin 1 to COM 1 pin 7 RTS
Hardy GND pin 5 to COM 1 pin 5 SIG GND

If these don't work;
1. Verify you are connected to the host comm. port you think you are.
2. You cannot use a serial communications option card from the HI 2151/20 in the HI 2151/30WC controller.
3. All serial communications uses the universal communications port J3.
4. Measure the voltages to see if the COM port is functioning.

5. Insure the CTS pin is pulled high. The HI 2151/30 unit will not transmit data if the CTS line is not pulled high.
6. Don't cross connect any other pins on the COM 1, 9-pin connector. There are pins that are jumpered together if using a 25-pin COM. port. DSR (6) to, DCD (8), to DTR (20) this forces DTR high on the host side.

It is possible that your COM port on the HI 2151/30WC or the PC is inoperative.