5.1.3 Energy Measurements
Imported/Exported active energy........
Imported/Exported reactive energy.....
Total active energy................
Total reactive energy............
5.2 Measured Inputs
2 Voltage inputs through 4-way fixed connector with 25mm
2
stranded wire capacity. single
phase two wire (1 p2w), three phase three wire (3p3w) or three phase four wire (3p4w)
unbalanced. Line frequency measured from L 1 voltage or L3 voltage.
5.3 Interfaces for External Monitoring
Three interfaces are provided:
RS 485 communication channel that can be programmed for Modbus RTU protocol
Pulse output 1 indicating real-time measured energy (configurable)
Pulse output 2 400imp/kWh (not configurable)
The Modbus configuration (baud rate etc.) and the pulse relay output assignments (kW/kVArh,
import/export etc.) are configured through the set-up screens.
5.3.1 Pulse Output
The pulse output can be set to generate pulses to represent kWh or kVArh.
Rate can be set to generate 1 pulse per:
0.01 = 10 Wh/VArh
0.1 = 100 Wh/VArh
1 = 1 kWh/kVArh
10 = 10 kWh/kVArh
100 = 100 kWh/kVArh
Pulse width 200/100/60 ms
Contact range 5-27V DC Max. current Input: 27mA DC
The test pulse output is a polarity dependent, passive transistor output requiring an external
voltage source for correct operation. For this external voltage source, the voltage (Ui) should
be 5-27V DC, and the maximum input current (Imax) should be 27mA DC. To connect the
impulse output, connect 5-27V DC to connector 7 (anode), and the signal wire(s) to connector 6
(cathode). The meter pulse is indicated on the front panel.
Attention: Pulse output must be fed as shown in the wiring diagram above. Scrupulously
respect polarities and the connection mode. Opto-coupler with potential-free SPST-NO contact.
5.3.2 RS485 Output for Modbus RTU
For Modbus RTU, the following RS485 communication parameters can be configured from the
set-up menu:
Baud rate 2400, 4800, 9600, 19200, 38400
Parity none / odd / even
Stop bits 1 or 2
RS485 network address nnn - 3-digit number, 001 to 247
Please contact us if your require the Modbus/Mbus protocol document.
5. Specification
5.1 Measured Parameters
The unit can monitor and display the following parameters of a single phase two wire(1p2w),
three phase three wire(3p3w) or four phase four wire(3p4w) system.
5.1.1 Voltage and Current
Phase to neutral voltages 100 to 276V a.c. (not for 3p3w supplies).
Voltages between phases 173 to 480V a.c.
Percentage total voltage harmonic distortion (THD%) for each phase to N ( not for 3p3w supplies).
Percentage voltage THD% between phases (three phase supplies only).
Current THD% for each phase
5.1.2 Power factor and Frequency and Maximum Demand
Frequency in Hz
Instantaneous power:
Power 0 to 96000 W
Reactive power 0 to 96000 VAr
Volt-amps 0 to 96000 VA
Maximum demanded power since last Demand reset Power factor
Maximum neutral demand current, since the last Demand reset (for three phase supplies only)
3 phase 4 wire
3 phase 3 wire
1 phase 2 wire
11.1 Mains/Load Connections
L1 L2 L3 N
L1 L2 L3 N
1
2
3
4
5
6
7
8
L1
L2
L3
L1
L2
L3
1
2
3
4
5
6
7
8
L1
N
L1
N
1
2
3
4
5
6
7
8
The HT-400 can be supplied with two wiring configurations: Mains entering at the top, load at
the bottom - see fig.A; or mains entering at the bottom, load at the top - see fig.B.
MAINS
LOAD
Fig.A Mains at the top
11. Wiring Diagrams
WARNING
Important Safety Information is contained in sections 7-8. Familiarize yourself with this
information before attempting installation or other procedures. Symbols used in this document:
Risk of Danger: These instructions contain important safety information. Read them before
starting installation or servicing of the equipment.
Caution: Risk of Electric Shock
7. Maintenance
In normal use, little maintenance is needed. As appropriate for service conditions, isolate
electrical power, inspect the unit and remove any dust or other foreign material present.
Periodically check all connections for freedom from corrosion and screw tightness, particularly if
vibration is present.
The front of the case should be wiped with a dry cloth only. Use minimal pressure, especially
over the viewing window area. If necessary wipe the rear case with a dry cloth. If a cleaning
agent is necessary, isopropyl alcohol is the only recommended agent and should be used
sparingly. Water should not be used. If the rear case exterior or terminals should be
contaminated accidentally with water, the unit must be returned to Autometers Systems Ltd for
inspection and testing.
8. Installation
The meter is designed to be fitted on a DIN rail in a suitable enclosure. The unit is intended for
use in a reasonably stable ambient temperature within the range -25°C to +55°C. Do not fit the
meter where there is excessive vibration or in excessive direct sunlight.
Please note terminal covers should be fitted and sealed.
See connection diagrams pages 14-15.
8.1 Safety
The unit is designed in accordance with IEC 61010-1:2010 – Permanently connected use, Normal
condition. Installation category III, pollution degree 2, basic insulation for rated voltage.
9. Electrician.
The HT-400 DIN rail meter should only be installed by a fully qualified electrician who has
knowledge of electricity meters connected with current transformers.
It is the installer who is fully responsible for the safe installation of this meter. It must be
installed to meet the current electrical regulations concerning installation of electricity meters.
10. EMC Installation Requirements
Whilst this unit complies with all relevant EU EMC (electro-magnetic compatibility) regulations,
any additional precautions necessary to provide proper operation of this and adjacent
equipment will be installation dependent and so the following can only be general guidance:
Avoid routing wiring to this unit alongside cables and products that are, or could be, a source of
interference.
5.4 Accuracy
Voltage .......................................
Current.......................................
Frequency..................................
Power factor..............................
Active power (W).......................
Reactive power (VAr)................
Apparent power (VA)................
Active energy (Wh)....................
Reactive energy (VARh)............
THD.............................................
Response time to step input...
5.5 Reference Conditions of Influence Quantities
Influence Quantities are variables that affect measurement errors to a minor degree. Accuracy
is verified under nominal value (within the specified tolerance) of these conditions.
Ambient temperature.......................
Input waveform.................................
Input waveform.................................
5.6 Environment
Operating temperature............
Storage temperature................
Relative humidity.......................
Altitude.......................................
Warm up time............................
Vibration.....................................
Shock..........................................
* Maximum operating and storage temperatures are in the context of typical daily and seasonal
variation.
5.7 Mechanics
DIN rail dimensions.............
Mounting..............................
Sealing...................................
Material.................................
6. Dimensions
The meter is a four module DIN rail mounted meter.
Dimensions are 72mm width x 100mm height x 66mm deep
The cut out hole for the front of the enclosure is 73mm x
46mm
The auxiliary supply to the unit should not be subject to excessive interference. In some cases, a
supply line filter may be required.
To protect the product against incorrect operation or permanent damage, surge transients must
be controlled. It is good EMC practice to suppress transients and surges at the source. The unit
has been designed to automatically recover from typical transients; however in extreme
circumstances it may be necessary to temporarily disconnect the auxiliary supply for a period of
greater than 10 seconds to restore correct operation.
Screened communication leads are recommended and may be required. These and other
connecting leads may require the fitting of RF suppression components, such as ferrite
absorbers, line filters etc., if RF fields cause problems.
It is good practice to install sensitive electronic instruments that are performing critical functions
in EMC enclosures that protect against electrical interference causing a disturbance in function.
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