Flowserve L75 User Manual

USER INSTRUCTIONS

L75 Series Electric Actuator

Modbus RTU Electronic Positioner

FCD LMAIM7502-00 – 07/05

Installation

Operation

Maintenance

Experience In Motion

L75 Series Electric Actuator — Modbus RTU FCD LMAIM7502-00 – 07/05

Contents

Introduction 4 Principles of Operation 4 General Environmental Information 4 Mechanical Installation 5 Electrical Connections 5 Adjustment of Switch Cams 7 Board Indicators 7 Termination Resistors 7 Conﬁguration 8

Modbus Address Selection 8 Baud Rate Selection 8 Two-Wire or Four-Wire Bus Selection 8

Modbus Functions 8

Modbus RTU Message Format 9 Reception of Invalid Commands 13 Reception of Commands with Illegal Fields 14 Modbus Exception Responses 14

Troubleshooting 15

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L75 Series Electric Actuator — Modbus RTU FCD LMAIM7502-00 – 07/05

Introduction

The Modbus RTU electronic positioner utilizes the RTU (Remote Terminal Unit) transmission mode to communicate on standard Modbus networks. The mode and other serial parameters (baud, parity, stop bits, etc.) must be conﬁgured the same for all devices on a Modbus network.

Principles of Operation

The Flowserve Modbus RTU Interface Card is a valve automation and control product that uses the Modbus communication protocol to operate and monitor position as well as provide predictive and preventative maintenance functions.

When power is ﬁrst applied to the board, the motor drive circuits are inactive and the valve will remain in its current position. A valve position is maintained until a Modbus movement command is received. Modbus functions are viewed as commands and are available to start or stop movement in a particular direction, to read the status of the end-of-travel limit switches, and to read the status of the motor drive circuits. If all three indicator LEDs blink simultaneously when power is ﬁrst applied, the Modbus address is not correct and the actuator will not operate. Refer to Modbus Address Selection in the Conﬁguration section to correct the problem.

Using a Modbus command, the valve shaft can be rotated either clockwise (CW) or counterclockwise (CCW). A movement command will cause rotation in a speciﬁed direction. Valve movement will continue until either the end-of-travel limit switch opens, or a stop command is received. In full open/close applications, the stop command is not needed. In other applications, the valve can be stopped in mid-travel by issuing a stop command before the end-of-travel limit switch opens.

It is not possible to command movement in both CW and CCW directions simultaneously. If this is attempted, the last positioning command will remain in effect. If a command is issued to move in a direction opposite to the current direction of movement, the actuator will stop movement in the current direction, delay for one second, and then begin moving in the speciﬁed direction (i.e. a stop command is not needed to change directions).

General Environmental Information

The L75 Modbus RTU Electronic Positioner is sensitive to electrical noise on communication and power supply lines. The positioner can also be affected by radiated electrical noise. For best positioner operation, the electrical noise level should be as low as possible. Follow the wiring guidelines in this manual carefully.

Shielded, twisted-pair wire is recommended for the communication cable. If shielded, twisted-pair wire is not available, non-shielded twisted pair cable is the next best alternative to prevent susceptibility to electrical noise. Unshielded, non-twisted cable is not recommended.

L75 Series Electric Actuator — Modbus RTU FCD LMAIM7502-00 – 07/05

Flowserve recommends an indoor storage environment suitable for human occupancy if the product must be stored prior to installation. Do not store the positioner in any of the following conditions:

Where exposure to relative humidity is greater than 85%.

Where acid or alkali fumes are present.

Where ultraviolet or other radiation is above normal background conditions.

Where temperatures are above 120°C or are below -40°C

Within 50 feet of any source of ozone.

Operating solid-state electronic equipment near or beyond its high temperature ratings is the primary cause for most failures. It is very important to consider factors that affect this product’s operating temperature. Operating an electronic device at or below its low temperature rating may result in inoperability. Proper operation usually resumes when rated operating temperatures are established. Low-temperature problems can be easily cured by addition of a thermostatically controlled heater to the actuator housing.

Flowserve has manufactured this product using moisture-prooﬁng and fungicidal coatings. The coatings provide added protection against the affects of high humidity. Where relative humidity is consistently 80% to 90% and the ambient temperature is subject to large variations, a heater/thermostat option should be installed in the actuator housing. The heater should not increase the internal temperature beyond the rated operating temperature.

Table 1: Electronic Printed Circuit Board Speciﬁcations

Power requirements

8345 / 8354 Modbus RTU Interface Card 120 VAC – 50 mA max.

8336 / 8366 Modbus RTU Interface Card 240 VAC – 25 mA max

Device Modbus

Firmware Revision 5/6/00

Transmission Speed 9.6 or 19.2 Kbaud maximum

Temperature

Operational -40°F to 150°F (-40°C to 65°C)

Storage -40°F to 250°F (-40°C to 120°C)

Mechanical Installation

Installation is best performed at the factory using brackets and mounting hardware designed for the purpose. Factory-trained individuals must perform installation and calibration in any event. Field upgrade of a non-Modbus unit to Modbus unit is possible with the proper hardware and training.

Electrical Connections

CAUTION: To prevent ignition of hazardous atmospheres, keep cover bolts tight while circuits

a

are live. Disconnect supply circuit before opening.

Entry into the actuator housing is made through one of the NPT conduit entries. Electrical data connections are made to a captive screw cage terminal strip located on the Modbus RTU board. Electrical power (120 VAC) and limit switch connections are made to the actuator terminal strip.

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