Where do I get 5 volts to keep CTS high in a HI 2151/30WC?

We are using a HI 2151/30WC with the B12 Profibus option. We have implemented serial communications (RS-232) from the Hardy to a third party display (wiring just the TXD and GND signals). We configured the Hardy for continuous print of Gross weight. In order to initiate communications we were told we have to apply a positive voltage to the CTS in the Hardy. We tested this using a 9 V battery and the communications worked. Is there somewhere on the Hardy unit that we could pick up this voltage to keep CTS high (as opposed to using an external source)?

We do not recommend using the 5 Volt supply from the weight controller to control communications. A power imbalance caused by the communications cable or host control has been known to cause memory problems with the weight controller.

The CTS signal level should be controlled and taken high from the RTS on the communications computer end of the serial cable. PIN 7 on a 9 pin connector and pin 4 on the DB 25 connector. It may be necessary to jumper the computer end DSR to DCD to DTR. This will raise the RTS high and provide the required communications control.

If your host does not or cannot provide the 5-12 VDC, an external power supply will be required.  A small 9 VDC battery hung on the back will maintain that CTS level for years.