Multi-Tech Systems 7500, 7600 manual Power Requirements, Communications Considerations

Models: 7500 7600

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ION 7500 / ION 7600 User’s Guide

Expansion Boards for Meters with Modbus Master Capability

 

 

Power Requirements

The Modbus controller requires 1 Amp at 5Vdc. The I/O modules require between 10-150mA depending on module type.

Description

Maximum draw per channel for I/O

 

 

Controller

1A

 

 

Rack

40mA

 

 

Digital Inputs

20mA

 

 

Digital Outputs

20mA

 

 

Analog Voltage Input

75mA

 

 

Analog Current Input

75mA

 

 

Analog Voltage/Current Outputs

200mA

 

 

Thermocouple Modules

75mA

 

 

The 5-Amp power supply can support the Modbus controller (1 Amp) plus two full racks of digital I/O that fit on a DIN rail rack.

Communications Considerations

The OpenDAC controller provides four wire RS-485 with the Modbus RTU protocol. To get two additional RS-485, connect a jumper wire between the two negative and positive terminals.

The Unit ID is set with two dial switches. One switch sets the low word of the ID (0x0 to 0xF) and the other sets the high word. Protocol and baud rate are set with the third dial switch, common settings are as follows:

Switch Setting

Parameters

 

 

0

9600 baud Modbus RTU

 

 

1

19 200 baud Modbus RTU

 

 

Remaining settings are for higher baud rates or ASCII protocol

NOTE

Detailed setup information for the Grayhill OpenDAC system is available at www.grayhill.com and in Bulletin #812, OpenDAC Modbus Configuration, Installation and Troubleshooting manual. Part numbers are available on the Power Measurement order form.

Digital and Analog I/O Technical Note

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Multi-Tech Systems 7500 Power Requirements, Communications Considerations, Description Maximum draw per channel for I/O