Meter Fixing, PT & CT Wiring, RS 485 Networking, Programming
Connection or disconnection from the ICD’s distribution system is to be done only by authorized company personnel. Customer personnel are not permitted to climb supply poles or access ICDs underground facilities, or make any new connections to ICD lines. Only under circumstances specified in the SAFETY, UNLOCK, OPEN and/or De-energize section in the agreement, customers may connect or disconnect from the distribution system.
We will issue specific instructions for cutting meter seal during emergencies. Such operations are carried out by authorized company personnel. We do not permit non-company personnel to relocate or remove any company meter.
PT and CT Wiring
The PT voltage and CT current inputs are vital for energy measurement. The accuracy class and phase shift of PTs and CTs used determines the accuracy of energy measurement. Accurate measurement requires instrument class 1 PTs and CTs. Another important point to be considered is proper rating of PT burden and appropriate wiring length of CT. Selection of CT primary current should be done in such a way that load current varies from 25 to 75% of its full-scale value.
Communication Port Details
We provide an optically isolated RS 485 communication port, which is a choice that needs to be specified while ordering. Similarly, the communication protocol – MODBUS RTU or MODBUS ASCII, needs to be specified while ordering. The meters are usually connected in multidrop network and data is collected in a centralized control room using standard SCADA software. The PC and instrument communicate in Master-Slave mode, where the PC sends a command address which is picked by the slave with matching address.
Proper programming of all meters is essential for smooth functioning. The table below shows the items to be programmed. All meters are provided a password for preventing alteration of configuration by unauthorized personnel.
|Configuration Item||In Meter|
|New pass word||In All meters|
|Primary Voltage||In All meters|
|Secondary Voltage||In All meters|
|Primary Current||In All meters|
|Secondary Current||In All meters|
|Wiring Type||In All meters|
|Modbus Address||Meters with Communication Interface only|
|kWh & Run Hour reset||All meters|