Guide to using Keller Level & Pressure transmitters with the Precision Digital PD865

This guide will help walk you through the configuration required to use a Keller MODBUS-capable level or pressure transmitter with the Precision Digital PD865 display. Jose, from Precision Digital, recently made video using this very same configuration, which you can watch here.

So just what is the PD865? The PD865 (also called ‘Snooper MODBUS Meter’) is an advanced panel meter made by Precision Digital that can poll and display data from the registers of virtually any device that supports MODBUS Function 3 or 4. It just so happens that Keller digital pressure & level transmitters fully support MODBUS Function 3. This means that we can use the PD865 (or virtually any other MODBUS capable panel meter) to display pressure or temperature data as measured by the Keller transmitter.

To accomplish this you will need at least one Keller digital transmitter, such as the Acculevel or Preciseline, and at least one Precision Digital PD865 (two if you wish to display pressure and temperature simultaneously). That’s it!

Here are some files that you may find helpful if you wish to do more than what is outlined in this basic guide:

PD865 Manual (requires log-in on the Precision Digital website)

Keller Transmitter User Guide

Series 30 Protocol Documentation (See page 20 for information on MODBUS as it relates to Keller transmitters)

Application note for using a PD865 & Keller transmitters

Connecting the devices:

Connect the Keller transmitter to the PD865 according to the following diagram:

Consult page 16 of the PD865 manual for more details.

Configuring the PD865:

Configure the PD865 settings with the following parameters:

Mode = Master

Function = 03

PV Number = 1 (number of PVs)

Slave ID = 001 (Device’s MODBUS address)

Reg. Number PV1 = 40003 (Register 0x02)

Data Type = Float

Byte Order = 1234

Poll Time = 1.0 seconds

Response Timeout = 5.0 seconds

Baud = 9600

Parity = none

Stop Bits = 1

Byte-to-Byte Timeout = 0.01 seconds

Configure the scaling of the PD865 with the following settings:

Input 1 = -19.9999

Input 2 = 99.9999

Display 1 = -19999.9

Display 2 = 99999.9

That’s it! Now you should see the pressure displayed on the PD865!