CET PMC-D726M User manual

PMC-D726M

Digital Multifunction Meter

User Manual

Version: V1.1

September 23, 2022

CET Electric Technology

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This manual may not be reproduced in whole or in part by any means without the express

written permission from CET.

The information contained in this manual is believed to be accurate at the time of publication;

however, CET assumes no responsibility for any errors which may appear here and reserves

the right to make changes without notice. Please consult CET or your local representative for

the latest product specifications.

DANGER

This symbol indicates the presence of danger that may result in severe injury or death and

permanent equipment damage if proper precautions are not taken during the installation,

operation or maintenance of the device.

CAUTION

This symbol indicates the potential of personal injury or equipment damage if proper

precautions are not taken during the installation, operation or maintenance of the device.

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DANGER

Failure to observe the following instructions may result in severe injury or

death and/or equipment damage.

➢

Installation, operation and maintenance of the meter should only be

performed by qualified, competent personnel that have the appropriate

training and experience with high voltage and current devices. The meter must

be installed in accordance with all local and national electrical codes.

➢

Ensure that all incoming AC power and other power sources are turned OFF

before performing any work on the meter.

➢

Before connecting the meter to the power source, check the label on top of

the meter to ensure that it is equipped with the appropriate power supply, and

the correct voltage and current input specifications for your application.

➢

During normal operation of the meter, hazardous voltages are present on its

terminal strips and throughout the connected potential transformers (PT) and

current transformers (CT). PT and CT secondary circuits are capable of

generating lethal voltages and currents with their primary circuits energized.

Follow standard safety precautions while performing any installation or service

work (i.e. removing PT fuses, shorting CT secondaries, …etc).

➢

Do not use the meter for primary protection functions where failure of the

device can cause fire, injury or death. The meter should only be used for

shadow protection if needed.

➢

Under no circumstances should the meter be connected to a power source if it

is damaged.

➢

To prevent potential fire or shock hazard, do not expose the meter to rain or

moisture.

➢

Setup procedures must be performed only by qualified personnel familiar with

the instrument and its associated electrical equipment.

➢DO NOT open the instrument under any circumstances.

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Limited warranty

➢

CET offers the customer a minimum of 12-month functional warranty on the

meter for faulty parts or workmanship from the date of dispatch from the

distributor. This warranty is on a return to factory for repair basis.

➢

CET does not accept liability for any damage caused by meter malfunctions. CET

accepts no responsibility for the suitability of the meter to the application for

which it was purchased.

➢

Failure to install, set up or operate the meter according to the instructions herein

will void the warranty.

➢

Only CET’s duly authorized representative may open your meter. The unit should

only be opened in a fully anti-static environment. Failure to do so may damage

the electronic components and will void the warranty.

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Table of Contents 
Chapter 1 Introduction ............................................................................................................................. 7 
1 Overview .................................................................................................................................... 7 
2 Features ...................................................................................................................................... 7 
3 PMC-D726M’s Application in Power and Energy Management Systems ................................... 8 
4 Getting more information .......................................................................................................... 9 
Chapter 2 Installation ............................................................................................................................. 10 
1 Appearance .............................................................................................................................. 10 
2 Dimensions ............................................................................................................................... 11 
2.1 Main Unit ...................................................................................................................... 11 
2.2 Terminals ....................................................................................................................... 12 
2.3 SCCTs ............................................................................................................................. 12 
3 Mounting .................................................................................................................................. 14 
4 Wiring connections .................................................................................................................. 15 
4.1 3-Phase 4-Wire (3P4W) Wye Direct Connection with 3CTs .......................................... 15 
4.2 3-Phase 4-Wire (3P4W) Wye Direct Connection with 2CTs .......................................... 16 
4.3 3-Phase 3-Wire (3P3W) Open Delta with 2PTs and 3CTs .............................................. 16 
4.4 3-Phase 3-Wire (3P3W) Open Delta with 2PTs and 2CTs .............................................. 17 
5 Communications Wiring ........................................................................................................... 17 
6 Digital Input Wiring .................................................................................................................. 18 
7 Digital Output Wiring ............................................................................................................... 18 
8 Analog Output Wiring .............................................................................................................. 18 
9 Power Supply Wiring ................................................................................................................ 18 
Chapter 3 Front Panel ............................................................................................................................. 19 
1 Display ...................................................................................................................................... 19 
1.1 LCD/LED Testing ............................................................................................................ 19 
1.2 LCD Display Areas .......................................................................................................... 20 
1.3 LED Display Symbols ..................................................................................................... 21 
2 Using the Front Panel Buttons .................................................................................................. 21 
3 LED Pulse Outputs .................................................................................................................... 21 
4 Display Screen Types ................................................................................................................ 21 
4.1 LCD Data Screens .......................................................................................................... 22 
4.2 LED Data Screens .......................................................................................................... 22 
5 Setup Configuration via the Front Panel .................................................................................. 23 
5.1 Making Setup Changes .................................................................................................. 23 
5.2 Setup Menu .................................................................................................................. 24 
5.3 Configuration ................................................................................................................ 25 
Chapter 4 Applications ........................................................................................................................... 28 
1 Inputs and Outputs .................................................................................................................. 28 
1.1 Digital Inputs ................................................................................................................. 28 
1.2 Digital Output................................................................................................................ 28 
1.3 Energy Pulse Outputs .................................................................................................... 28 
1.4 AO Output ..................................................................................................................... 28 
2 Power and Energy .................................................................................................................... 29 
2.1 Basic Measurements ..................................................................................................... 29 
2.2 Energy Measurements .................................................................................................. 29 
2.3 Demand Measurements ............................................................................................... 29 
3 Power Quality ........................................................................................................................... 30 
3.1 Phase Angles ................................................................................................................. 30 
3.2 Power Quality Parameters ............................................................................................ 30 
3.3 Unbalance ..................................................................................................................... 31 
4 Setpoints .................................................................................................................................. 31 
5 Logging ..................................................................................................................................... 33 
5.1 Peak Demand Log ......................................................................................................... 33 
5.2 SOE ................................................................................................................................ 33 
6 Time of Use (TOU) .................................................................................................................... 34 

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Chapter 5 Modbus Register Map ............................................................................................................ 35 
1 Basic Measurements ................................................................................................................ 35 
2 Energy Measurements ............................................................................................................. 36 
3 Harmonic Measurements ......................................................................................................... 37 
3.1 Power Quality Measurements ...................................................................................... 37 
3.2 Current Harmonic Measurements ................................................................................ 37 
3.3 Voltage Harmonic Measurements ................................................................................ 37 
4 Demands .................................................................................................................................. 38 
4.1 Present Demands .......................................................................................................... 38 
4.2 Peak Demand Log of This Month (Since Last Reset) ..................................................... 38 
4.3 Peak Demand Log of Last Month (Before Last Reset) ................................................... 38 
4.4 Demand Data Structure ................................................................................................ 38 
5 SOE Log ..................................................................................................................................... 38 
6 Device Setup ............................................................................................................................. 40 
6.1 Basic Setup Parameters ................................................................................................. 40 
6.2 I/O Setup Parameters .................................................................................................... 42 
6.3 Setpoints Setup ............................................................................................................. 42 
7 TOU Setup ................................................................................................................................ 43 
7.1 Basic .............................................................................................................................. 43 
7.2 Season ........................................................................................................................... 43 
7.3 Daily Profile ................................................................................................................... 43 
7.4 Alternate Days ............................................................................................................... 44 
8 Time .......................................................................................................................................... 45 
9 DO Control ................................................................................................................................ 45 
10 Meter Information.................................................................................................................. 46 
Appendix A Technical Specifications ....................................................................................................... 47 
Appendix B Standards Compliance ......................................................................................................... 49 
Appendix C Ordering Guide .................................................................................................................... 50 
Contact us ............................................................................................................................................... 51 
 

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Chapter 1 Introduction

This manual explains how to use the PMC-D726M Digital Multifunction Meter. Throughout the manual

the term “meter” generally refers to all models. Differences between the models are indicated with the

appropriate model number.

This chapter provides an overview of the PMC-D726M meter and summarizes many of its key features.

1.1 Overview

The PMC-D726M Digital Multifunction Meter is CET’s latest offer for the low-cost digital power/energy

metering market. Housed in an industry standard DIN form factor measuring 72mmx72mmx71.8mm

(LCD) or 72mmx72mmx76.8mm (LED), it is perfectly suited for industrial, commercial and utility

metering applications. The PMC-D726M features quality construction, true RMS multifunction

measurements and a LED or LCD display. Compliance with the IEC 62053-21 Class 1 kWh Accuracy

Standard, it provides optimum Price to Value ratio and is a cost effective replacement for traditional

analog instrumentation, capable of displaying 3-phase measurements at once. The PMC-D726M comes

standard with two Digital Inputs for status monitoring and two Digital Outputs for control. In addition,

it optionally provides Split-Core CT (SCCT) support for retrofit situations or one 0/4-20mA Analog Output

for interfacing with 3rd party SCADA system. The standard SOE Log records meter events such as power-

off, setup changes, DI status changes in 1ms resolution. With a standard RS-485 port and Modbus

protocol support, the PMC-D726M becomes a vital component of an intelligent, multifunction

monitoring solution for any Power and Energy Management systems.

You can setup the meter through its front panel or via our free PMC Setup software. The meter is also

supported by our PecStar® iEMS Integrated Energy Management System.

Following is a list of typical applications for the PMC-D726M:

▪ Analog meter replacement

▪ Industrial, Commercial and Utility panel metering

▪ Substation, Factory and Building Automation

▪ Sub-metering and Cost Allocation

▪ Ideal for retrofitting with SCCT option

Contact CET Technical Support should you require further assistance with your application.

1.2 Features

Ease of use

▪ Large, bright, backlit LCD or high-contrast LED display

▪ Front panel kWh and kvarh LED energy pulse outputs

▪ Password-protected setup via front panel or free PMC Setup software

▪ Easy installation with mounting clips, no tools required

Measurements

▪ ULN, ULL per phase and Average

▪ Current per phase and Average with calculated Neutral

▪ kW, kvar, kVA, P.F. per phase and Total

▪ Bi-directional energy measurements

▪ Frequency

PQ Measurements*

▪ THD, TOHD, TEHD and Individual Harmonics up to 31st

▪ TDD, K-Factor and Crest-Factor

▪ U and I Unbalance and Phase Angles

*Available in Firmware V1.00.04 (LED)/V1.01.04 (LCD) or later

Setpoints*

▪ 6 user programmable Setpoints with extensive list of monitoring parameters including Voltage,

Current, Power and Demand

▪ Configurable Threshold and Time Delay

▪ SOE Logging and DO trigger

*Available in Firmware V1.00.04 (LED)/V1.01.04 (LCD) or later

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SOE Log

▪ 16 events time-stamped to ±1ms resolution

▪ Record all setup, Setpoint and Digital Input status changes

TOU and Demand*

▪ One TOU schedule, providing

o 6 Seasons

o 6 Daily Profiles, each with 6 Periods in 15-minute interval

o 10 Holidays or Alternate Days

o 4 Tariffs, each providing kWh and kvarh Imp/Exp and kVAh

▪ Demands and Peak Demands with Timestamp for per phase Current, kW Total, kvar Total and kVA

total

*Available in Firmware V1.00.04 (LED)/V1.01.04 (LCD) or later

Inputs and Outputs

▪ kWh and kvarh LED Energy Pulse Outputs on the Front Panel

▪ Two Digital Inputs for Status Monitoring

▪ Two Digital Outputs for Control applications*

▪ One optional Analog Output at 0/4-20mA

*The option of 2DIs + 2DOs is available in Firmware V1.00.03 (LED)/V1.01.03 (LCD) or later

Communications

▪ Optically isolated RS-485 port at 1200 to 19,200 bps

▪ Modbus RTU support

System Integration

▪ Supported by CET’s PecStar® iEMS and PMC Setup

▪ Easy integration into other Automation, SCADA or BMS systems via Modbus RTU

1.3 PMC-D726M’s Application in Power and Energy Management Systems

The PMC-D726M can be used to monitor Wye or Delta connected power system. Modbus

communications allow real-time data, events, DI status and other information to be transmitted across

a RS-485 network to an Integrated Energy Management system such as the PecStar® iEMS.

Figure 1-1 PMC-D726M’s application

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1.4 Getting more information

Additional information is available from CET via the following sources:

▪ Visit www.cet-global.com

▪ Contact your local representative

▪ Contact CET directly via email or telephone

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Chapter 2 Installation

2.1 Appearance

Figure 2-1 Appearance (LCD)

Figure 2-2 Appearance (LED)

Caution

Installation of the PMC-D726M should only be performed by qualified, competent

personnel that have the appropriate training and experience with high voltage and current

devices. The meter must be installed in accordance with all local and national electrical

codes.

During the operation of the meter, hazardous voltages are present at the input terminals.

Failure to observe precautions can result in serious or even fatal injury and equipment

damage.

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Figure 2-3 Rear Panel

2.2 Dimensions

2.2.1 Main Unit

Figure 2-4 Dimension (LCD)

Figure 2-5 Dimensions (LED)

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2.2.2 Terminals

Figure 2-6 Terminal Dimensions

Terminal

Terminal Dimensions

Wire Size

Max. Torque

1

DI/DO/AO

2.6mm x 3.3mm

1.5mm2

5 kgf.cm/M3

(4.3 lb-in)

RS-485

Power Supply

2

Current Input/Voltage Input

6.4mm x 6.4mm

1.0mm2 - 2.5mm2

(14AWG - 22AWG)

6.0 kgf.cm/M3

(5.2 lb-in)

Table 2-1 Terminal Dimensions

2.2.3 SCCTs

▪ PMC-SCCT-5A-2mA-A

Figure 2-7 PMC-SCCT-5A-2mA-A Dimensions

▪ PMC-SCCT-100A-40mA-16-A

Figure 2-8 PMC-SCCT-100A-40mA-16-A Dimensions

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▪ PMC-SCCT-200A-40mA-24-A

Figure 2-9 PMC-SCCT-200A-40mA-24-A Dimensions

▪ PMC-SCCT-400A-40mA-35-A

Figure 2-10 PMC-SCCT-400A-40mA-35-A Dimensions

▪ PMC-SCCT-800A-40mA-A

Figure 2-11 PMC-SCCT-800A-40mA-A Dimensions

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2.3 Mounting

The PMC-D726M should be installed in a dry environment with no dust and kept away from heat,

radiation and electrical noise source.

Installation steps:

▪ Remove the installation clips from the meter

▪ Fit the meter through a 68mmx68mm cutout as shown in Figure 2-12 (LCD) or Figure 2-13 (LED)

▪ Re-install the installation clips and push the clips tightly against the panel to secure the meter

Figure 2-12 Panel Cutout (LCD)

Figure 2-13 Panel Cutout (LED)

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2.4 Wiring connections

PMC-D726M can satisfy both Wye and Delta three phase power systems. Please read this section

carefully before installation and choose the correct wiring method for your power system. The following

Wiring Modes are supported:

▪ 3-Phase 4-Wire (3P4W) Wye Direct Connection with 3CTs

▪ 3-Phase 4-Wire (3P4W) Wye Direct Connection with 2CTs

▪ 3-Phase 3-Wire (3P3W) open Delta with 2PTs and 3CTs.

▪ 3-Phase 3-Wire (3P3W) open Delta with 2PTs and 2CTs

2.4.1 3-Phase 4-Wire (3P4W) Wye Direct Connection with 3CTs

Please consult the serial number label to ensure that the system phase voltage is less than or equal to

the meter’s voltage input specification. Set the Wiring Mode to Wye.

Figure 2-14 3-Phase 4-Wire Wye, no PTs, 3 CTs

Caution

Under no circumstances should the PT secondary be shorted.

Under no circumstances should the CT secondary be open when the CT primary is energized.

CT shorting blocks should be installed to allow for easy maintenance.

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2.4.2 3-Phase 4-Wire (3P4W) Wye Direct Connection with 2CTs

Please consult the serial number label to ensure that the system phase voltage is less than or equal to

the meter’s voltage input specification. Set the Wiring Mode to Wye.

Figure 2-15 4-Wire Wye, no PTs, 2 CTs

2.4.3 3-Phase 3-Wire (3P3W) Open Delta with 2PTs and 3CTs

Please consult the serial number label to ensure that the rated PT secondary voltage is less than or

equal to the meter’s rated phase voltage input specification. Set the Wiring Mode to Delta.

Figure 2-16 3-Phase 3-Wire Delta, 2PTs, 3CTs

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2.4.4 3-Phase 3-Wire (3P3W) Open Delta with 2PTs and 2CTs

Please consult the serial number label to ensure that the rated PT secondary voltage is less than or

equal to the meter’s rated phase voltage input specification. Set the Wiring Mode to Delta.

Figure 2-17 3-Phase 3-Wire Delta, 2PTs, 2CTs

2.5 Communications Wiring

The PMC-D726M provides one RS-485 port and supports the Modbus RTU protocol. Up to 32 devices

can be connected on a RS-485 bus. The overall length of the RS-485 cable connecting all devices should

not exceed 1200m.

If the master station does not have a RS-485 communications port, a RS232/RS-485 or USB/RS-485

converter with optically isolated output and surge protection should be used. The following figure

illustrates the RS-485 connections on the PMC-D726M.

Figure 2-18 RS-485 with SH (AO Option) Connections

Figure 2-19 RS-485 (2xDI+2xDO Option) Communications Connections

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2.6 Digital Input Wiring

The following figure illustrates the Digital Input connections on the PMC-D726M:

Figure 2-20 DI Connections

2.7 Digital Output Wiring

The following figure illustrates the Digital Output connections on the PMC-D726M:

Figure 2-21 DO Connections

2.8 Analog Output Wiring

The following figure illustrates the Analog Output connections on the PMC-D726M:

Figure 2-22 AO Connections

2.9 Power Supply Wiring

For AC supply, connect the live wire to the L/+ terminal and the neutral wire to the N/- terminal.

For DC supply, connect the positive wire to the L/+ terminal and the negative wire to the N/- terminal.

Figure 2-23 Power Supply Connections

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Chapter 3 Front Panel

The PMC-D726M meter has a large, bright, backlit LCD or a high-contrast LED display and four buttons

for data display and meter configuration. This chapter introduces the front panel operations.

Figure 3-1 Front Panel (LCD)

Figure 3-2 Front Panel (LED)

3.1 Display

3.1.1 LCD/LED Testing

Pressing both the <Phase> and the <Energy> buttons simultaneously for 2 seconds enters the LCD/LED

Testing mode. All LCD/LED segments and LED indicators are illuminated during testing. The LCD/LED will

return to its normal display mode when any button is pressed.

Figure 3-2 Full LED/LCD Display

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3.1.2 LCD Display Areas

This section provides a description of the LCD display areas. The PMC-D726M with LCD display can

generally be divided into 4 areas:

A: Measurement values

B: Measurement symbols for parameters such as Voltage, Current, THD, Unbalance, PF, Voltage

Phase Angle, Current Phase Angle and Demand, ..etc.

C: Measurement Units, Communication indicator and PF Quadrant status

D: DI Status and DO Status indicators as well as Energy Type such as Imp/Exp/Net/Total

Figure 3-3 LCD Display

The following table shows the special LCD display symbols:

Area

Label

Description

B

Voltage

Current

kW

kvar

kVA

K-Factor

Frequency

Phase A

Phase B

Phase C

THD

Unbalance

Demand

Line to Neutral

Line to Line

Negative Symbol

Maximum

Minimum

Phase Angle

Power Factor

C

Measurement Units for Frequency (Hz), Power (W, var, VA), Energy (Wh, varh,

Vah), Current (mA) and Temparature (°C)

Harmonic

Distortion Unit

COM Port Status

Alarm Symbol

PF Quadrant –

Q1/Q2/Q3/Q4

D

DI Open

DI Close

DO Open

DO Close

Import

Export

Net

Total

Table 3-1 LCD Display Symbols

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CET PMC-D726M User manual

CET PMC-D726M User manual

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