How do you communicate bi-directionally with a HI 2151/30WC?

I'm trying to communicate bi-directionally with my HI 2151/30WC using RS-232 protocols. I read and followed the specifications mentioned in section 4 of the manual but I was unable to succeed. Here are the parameters that the instrument is set at:

Ser Con = Bi-dir;
Baud = 9600;
Parity = None;
Stop = 1 bit;
Length = 8 bits;
Format = Net only and in continuous print mode;
Control = Software;
Echo = Off; Address = 10;

How do you communicate bi-directionally with a HI 2151/30WC?

Serial communication commands are explained in the HI 2151/30WC manual, see the attached Tech Note for additional information.

Successful setup and testing of your HI 2151/30 RS 232 serial communications verifies that the wires and connectors are correct and the comm port is good. To test the setup you can stream the data from the serial port to your host communications package, 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.

Setup; baud 19,200, 8-N-1, Control = Hardware, RS 232, Echo = OFF, Address 00, Ser Con = 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.

With this setup, you should be getting data in the Hyper-terminal program if you go online.  If you do not get data, then check the voltage levels.

Voltage checks; RS 232

Signal ground to CTS = +10 volts, when hooked to the COM 1, RTS pin seven, and communications is active. Read -6 v when no communications is started or established.  NOTE: Unit will not transmit any data unless the CTS line is pulled high.

Signal ground to TXD is +10 volts 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 2151/20WC 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. Don't cross connect any other pins on 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.

Once