YZBK-II carrier communication system is part of the coal handling control system in a coal consuming company such s a thermal power plant. It realized remote data communication by using power supply of the impeller coal feeder, solved the problem of data communication of the mobile equipment in coal trench. It is one of the best solutions for communication of program controlled coal feeder in coal handling. It can serve in harsh environment.

Features
Carrier communication does not have the problems exist in wireless communications, such as strong electromagnetic interference, complex antenna set up, signaling instability (blind spots).
Using lines of power supply of coal feeder as signal transmission medium, laying a large number of signal cables is avoided, so maintenance workload from cable damage and aging is reduced. It also overcomes the problems of signal interference and high input impedance in the cable resulting from effects of distributed capacitance charge and discharge between cables because of laying cables in parallel.
Dead area of impeller coal feeder is eliminated, so spontaneous combustion of coal heap in the ditch can be avoided.Design length of underground coal trench and cost of coal trench can be reduced.Keep personnel on site away from dust and reduce the work intensity of maintenance staff. 

System Structure
The communication system consists of on-site transfer station and on-site subcomputer. On-site transfer station is located at the train unloading trench.

System Parameters

1.In-place transfer station:

(1) power supply AC220V
(2)PLC is Schneider TWIDO or Omron CPM2A series.

2.On-site sub-computer:

(1) Power supply: three-phase 380V
(2)PLC is Schneider TWIDO or Omron CPM2A series.

3.Communication:

(1) On-site transfer station and on-site sub-computer are of carrier communication.
(2) PC and on-site transfer station should adopt standard network communications if any communication is adopted. 
4.Communication media:

(1) On-site transfer station and the on-site sub-computer should adopt safety trolley conductor or cable. Dedicated trolley conductor or cable can be laid, and power line can also be used for communications. （2）上位(2) PC and on-site transfer station should adopt cable or shielded twisted pair cable.

5.Single scan time: <5 seconds (2 computers)
6. Communication Transmission rate:

(1) On-site transfer station and on-site sub-computer to be 1200bit / or 2400 bit
(2) PC and on-site transfer station: to be determined by the network

7.Operation: on-site manual and remote control (centralized control or program control)

8.Operating temperature: 0 ~ +40℃

9.Relative humidity of operating environment: 40℃ (20-90)% Rh, no condensation