Radio Crane Remote Control Systems

The receiver is crystallizationmonitored. A synthesized receiver for Crane Remote Control is an alternative for 72–76 MHz. An 8-bit micro-controller, operating at 4.9 MHz, translates the signal coming from the rf module and crosses the output commandments throughout the I/O panelsto the output modules.

The ac receiver utilizes 120V ac Stable State Transmission output modules. No equipmentbroadcasts arenecessary for controllers up to and comprising size four contactors. An LED shows the position ofthe output module. A step less, parallel output module is present; as is a transmission cardusing electro-mechanical output transmits. Input modules checks the level of the 120V acControl Power, The principal Contactor, plus M, F, R for everymovement.

 The output modules on the dc receiver are 270V dc Solid State Relays. No interfacerelays are needed for controllers up to and including size 5 contactors. The outputmodule status is shown by LED’s: red = output activated; green = output current flowing.Input modules monitor the status of the 250V dc Control Power, Main Contactor, plus M,F, R for each motion.

 Each transmitter/receiver pair has their own unique 7–bit address code (the first seven bits of the digital message). Unless the transmitter address and receiver address areidentical, the system will not respond to any command, regardless of the frequency.

Message integrity is assured by use of an 8-bit Cyclic Redundancy Check (CRC)code. Cyclic redundancy check is a division performed in the transmitter logic,which produces a remainder that is transmitted last as the 8-bit check code. Thereceiver logic performs a like division on the received message (without the CRC) toproduce its own 8–bit CRC code. If the two CRC codes are identical, the receivedmessage will be decoded as a “valid message” and the appropriate outputs will beturned on or off, as directed.