Multi-Tech Systems 7500 - Manual (Page 214)

Expansion Boards for Meters with Modbus Master Capability ION 7500 / ION 7600 User’s Guide
Page 214 Digital and Analog I/O Technical Note
Expansion Boards for Meters with Modbus Master Capability
For ION meters that have Modbus master capability, the Grayhill OpenDAC I/O
system provides extended functionality. The Grayhill OpenDAC system provides
serial Modbus RTU connections to the ION meter. Extended analog and digital
I/O capability are provided by the Grayhill OpenDAC rack.
OpenDAC controllers provide network connections but do not perform local
control, and are used most often with ION meters that have Modbus master
capability. OpenLine hardware modules fit into an OpenDAC rack to make up the
system. OpenLine hardware modules are dual-point modules, for example, one
digital input module has two input channels. The Series 73L modules are analog,
and measure or control voltage, current, or temperature. The Series 70L modules
are digital and are discrete — either on or off.
Grayhill OpenDAC controllers and hardware modules let you stack up two racks
for a total of 32 I/O points. You can also mix analog and digital inputs and outputs
on the same rack. You must have a power supply for each expansion board. These
power supplies are purchased separately.
In general, you require the following to use the OpenDAC system with an ION
meter that has Modbus master capability:
ION Meter with Modbus master capability
OpenDAC controller
One or two OpenDAC racks
Up to eight OpenLine hardware modules (per rack) up to 16 I/O points per rack
Five-volt, 5-Amp DC power supply (you may need more amperage if you using
current output modules)
OpenDAC Modbus Configuration Installation and Troubleshooting Guide,
Bulletin #812
Description
Maximum # of
Analog Inputs Maximum # of
Analog Outputs Maximum # of
Analog Devices Possible Maximum
Configurations
Board A WITHOUT Optional
Power Supply
6 6 6
Any combination up to 6 total
Board A WITH Optional Power
Supply
7 15 15
Board full
Board A WITHOUT Optional
Power Supply + Board B 13 21 21 A: 6 AI; B: 7 AI, 8 AO
A: 6 AO; B: 7 AI, 8 AO
A: 6 AO; B: 15 AO
A: 6 AI; B: 15 AO
Board A WITH Optional Power
Supply + Board B
14 30 30
Both boards full