Digital Voltage Regulator Caterpillar

The digital voltage regulator has the capability to communicate with a remote personal computer or programmable logic controller. The J1 connector of the digital voltage regulator provides a RS422 port necessary for communication. The RS422 port is a 5-wire communication media including a wire pair for Receive, a wire pair for Transmit, and a common Signal Ground. For noise immunity, it is required that the wire pairs be twisted and shielded. The shield(s) should be grounded at the remote end of the cable only. The common signal ground is NOT a bonding ground and should not be grounded to the case or frame. It is to be connected to the RS422 device Signal Ground connection point. Cable length should be limited to 1000 meters maximum for the RS422 signal wiring.

An isolated, regulated power supply is also required for the remote communication port to operate. The digital voltage regulator is optically isolated from the communications port to ensure complete isolation of voltage levels. In order to maintain this isolation, power for the communications circuitry must be provided from outside the regulator. The supply may be from 8.55 VDC to 10.35 VDC where 9 VDC is considered nominal and should be able to source 100 mA of current. This voltage is measured at the voltage regulator. If the supply is provided in a remote location, ensure that the voltage present at the regulator is still above 8.55 VDC (preferably at 9 VDC or slightly above).

A windows program is available to communicate with the digital voltage regulator. The program is called DVRVIEW. For proper connection of the digital voltage regulator to the personal computer, see Testing And Adjusting, "Wiring Diagrams", the illustration Remote Communications.

DVRVIEW allows the user to perform the following operations.

• Viewing and modifying the parameters in a windowed PC environment

• Sending a "recipe" of parameters to the digital voltage regulator

• Saving the existing digital voltage regulator settings to a recipe file

For the DVRVIEW supporting software and documentation, see Digital Voltage Regulator Software - 3.5" Disks, LERX5100. This reference includes a manual and a software. In order to obtain a copy of the manual only, order Digital Voltage Regulator Software - User Manual Only, LERX5662. The manual also contains the software protocol used to communicate with the digital voltage regulator. The protocol is very simple and can be implemented in switchgear or office equipment to provide customized communication with the digital voltage regulator.

An RS422 to RS232 (computer serial port) converter is available from the Caterpillar Parts Department. Use part number 131-7416 Converter Control. The converter comes with a regulated power supply and a wiring harness to connect the converter to the digital voltage regulator. A standard serial cable must be provided to connect the converter to a PC. If connecting to a modem, it may be necessary to use a null modem cable or adapter on the RS232 side of the converter. RS232 wiring should be limited to 15 m (50 ft).