Pin Car Control I/O Description1 Not connected –2 Not connected –3 Input TX –

(Transmit Data)4 Output RX +

(Receive Data)5 Not connected –6 Not connected –7 Input TX +

(Transmit Data)8 Output RX -

(Receive Data)9 Not connected –

EDUCATIONAL FOCUS: ELEVATOR COMMUNICATION

Serial communications is an important function tohave available in high-performance elevator drives.Using serial communications can allow the elevator carcontroller to monitor and control a variety of drive infor-mation, including operation, speed profile and statusmonitoring. Both Magnetek’s DC (DSD 412) and AC(HPV 900) elevator drives have this function available.The drives both communicate via a RS-422 serial portat 19,200 bits per second. The main advantage to serial communications is that a zero speed commandis truly zero.

Installation and Start-UpThe HPV 900 has a RS-422 serial port as standard with

every drive. While the DSD 412 needs to have the drivecontrol board with the RS-422 serial interface port (partnumber 46S02975-04xx).

The serial communications is full-duplex over a19,200 bit per sec, RS-422 channel. The serial data issent in bytes with one start bit, eight data bits, one stopbit and no parity.

On the HPV 900, the receive channel on the drive iso p t i c a l l y isolated. The transmit channel is not isolated.However, if the car controller optically isolates its receivechannel, and no other pins are connected, complete electricalisolation can be obtained between the car controller controland the drive control grounds.

The HPV 900/DSD 412 to car controller connection ismade with a straight through cable with a nine-pin D-Subconnector. Figures 3 and 4 show the signals used by theHPV 900 and DSD 412.

It is recommended that the drive’s transmission linebe terminated with a termination resistor of 100 ohmsone-half watt. The drive’s receiving line is already termi-nated internally in the drive with a 100-ohms one-half-watt resistor.Operation

The following functions can be performed with Magnetek’sstandard elevator serial protocol.HPV 900 Serial Functions

Following can be controlled via the serial port:◆ Speed Command◆ Run Command◆ High/Low Gain Control◆ Pre-Torque Command and Control◆ Overspeed Test◆ Torque Ramp Down Function◆ Auxiliary Torque Command◆ Mechanical Brake Control ◆ Fault Reset

Following can be monitored via the serial port:◆ Faults (both active and history)◆ Software Version Number and Cube Id◆ Status of all Hardware Logic Inputs and Outputs◆ Values of Various Drive Display Variables

The serial port also allows for read/write access to allparameters.

SERIAL COMMUNICATION

TO ELEVATOR DRIVESby Tony Frey

Figure 1 – HPV 900 AC Elevator Drive

Figure 2 – DSD 412 DC Elevator Drive

Figure 3 – Serial Port Pinout

Figure 4 – Wiring between HPV 900/DSD 412 and RS-422

DB-9 MaleC o n n e c t o r

R S - 4 2 2 on HPV- 9 0 0

TD(-) or TD(B) } { Pin 4 RX(+)

TD(+) or TD(A) } { Pin 8 RX(-)

RD(-) or RD(B) } { Pin 7 TX(+)

RD(+) or RD(A) } { Pin 3 TX(-)

DSD 412 Serial FunctionsFollowing can be controlled via the serial port:

◆ Speed Command◆ Run Command◆ High/Low Gain Control◆ Pre-Torque Command and Control◆ Torque Ramp Down Function◆ Motor Field Control◆ Fault Reset◆ PCDU Emulation

Following can be monitored via the serial port:◆ Faults (both active and history)◆ Demand Velocity◆ Values of Various Drive Display Variables

TroubleshootingHPV 900

The HPV 900 will declare a“COMM FAU LT” for the following:◆ Communications Time-Out (whendrive is running no message for 40m s e c )◆ Bad Message Checksum (three badchecksums in a row)DSD 412

The DSD 412 will declare a “F412”for the following:◆ Communications Time-Out (once

communications established, no message for over 150 msec)

Additional InformationFor additional information, please refer to the HPV 900

and DSD 412 Technical Manuals. Also, Magnetek Eleva-tor Products website, www.elevatordrives.com, containsdetailed application tips, as well as other technical infor-mation about its elevator products.

Tony Frey is Technical Support manager for Magnetek Elevator Products.

Figure 5 – HPV 900 Digital Operator

Figure 6 – DSD 412 Display