
147D Series Modbus Reference Guide EM-9501-C Rev.4
47D Series Digital Panel Meters
Modbus Protocol Reference Guide
CONTENTS
1. INTRODUCTION ...................................................................................2
2. MODBUS PROTOCOL..........................................................................3
2.1 GENERAL DESCRIPTIONS ..............................................................................................3
2.2 TRANSMISSION SETTING................................................................................................3
2.3 SYSTEM CONFIGURATION EXAMPLES ..........................................................................4
2.4 MODBUS MESSAGE FRAMING........................................................................................6
2.4.1 READ HOLDING REGISTERS ...............................................................................6
2.4.2 WRITE MULTIPLE REGISTERS.............................................................................7
2.4.3 CRC CALCULATION ALGORITHM.........................................................................8
3. MODBUS REGISTERS .........................................................................9
3.1 DEVICE INFORMATION ....................................................................................................9
3.2 I/O DATA ........................................................................................................................... 10
3.3 DEVICE CONTROL.......................................................................................................... 11
3.4 LOCKOUT SETTING........................................................................................................ 11
3.5 INPUT SETTING ..............................................................................................................12
3.5.1 COMMON SETTING.............................................................................................12
3.5.2 FORCED ZERO, TARE ADJUSTMENT V M AC .................................................12
3.5.3 DC VOLTAGE/CURRENT INPUT V....................................................................13
3.5.4 POTENTIOMETER INPUT M............................................................................. 13
3.5.5 RTD INPUT R..................................................................................................... 14
3.5.6 THERMOCOUPLE INPUT T............................................................................... 14
3.5.7 AC VOLTAGE/CURRENT INPUT V.................................................................... 15
3.6 BARGRAPH SETTING..................................................................................................... 16
3.7 ANALOG OUTPUT SETTING ..........................................................................................16
3.8 ALARM SETTING............................................................................................................. 17
3.8.1 COMMON SETTING.............................................................................................17
3.8.2 SETPOINTS & BANK SWITCHING ...................................................................... 18
3.8.3 ALARM TRIP ACTION........................................................................................... 19
3.9 OPERATION CONTROL SETTING.................................................................................. 19
3.10 DISPLAY SETTING ..........................................................................................................20
3.11 MODBUS SETTING .........................................................................................................20