Page 20 809-DM ManualCHAPTER 7 - SERIAL INTERFACE COMMANDSThe following section describes the defined 809-DM serialcommands. The serial data requests are ASCII data strings.Throughout this section represents a single carriage returncharacter (hexadecimal 0x0D). In this section Red text representsserial data being received by the 809-DM. Blue text representsserial data being transmitted from the 809-DM. Either uppercaseor lowercase characters can be used, the response will be in thecase that is used to make the request.To communicate with the gauge for testing purposes, the 809DMSerial Port Tester can be used. It has all of the serial commandspreprogrammed for easy reference. Press the correspondingbutton (or SHIFT and the button at the same time) followed byENTER to query the current setting of any of the parameters. Pressthe button followed by the number sequence as indicated on theTester screen, followed by ENTER to set any of the parameters. TheTester will interpret the gauge response with English phrases tomake it easy to know what the settings are.PTO changeDuring normal operations, a change of PTO status causes the 809-DM to send out a comma separated list of values correspondingto the PTO status followed by the number of channels beingmonitored. The transmit is done after a programmable delay.p,E,11.16,79.00, 0.00, 0.00, 0.00, 0.00The next example shows the PTO disengaged and only twochannels being monitored.p,D,11.16,79.00The next example shows the PTO engaged and all six compartmentshaving invalid data.p,E,NOSIG,NOSIG,NOSIG,NOSIG,NOSIG,NOSIGThe level reading will always be five characters including thedecimal place. If no decimal place is present a space character willpad the least significant byte. NOSIG shows no valid level data.ERROR shows level data error.Set PTO configurationThere are four items to configure:1. Resistor pullup on or off.2. PTO engagement polarity high or low.
