grifo® ModBUS Telecontrol

GMT English Tech. Manual PDF format.

GMT (grifo® ModBUS Telecontrol) is a "Complete Logic Protocol for Serial Communication" developed for the wide range of grifo® industrial cards.

This protocol is based on the famous ModBUS standard that, thanks to its world wide diffusion, ensures the employment either in old and new applications.
The GMT package is the result of numerous experiences, collected in many years, during the development of applications in the industrial environments. In this field the informations must be exchanged between intelligent systems through simple and cheap connections.

In general the ModBUS is a logic protocol that defines the communication rules, in fact it standardizes:

but it doesn't specify the electric and physic protocol. So the user can freely select, for example, the desidered Baud Rates, the electric driver used for connecction, and so on, to better satisfy its own requirements or to easily fit the features of a communication already developed.

This documentation assumes that the user already knows ModBUS and so this protocol is not here described. For those users that want a deeper knowledge it is suggested to examine the considerable information available on Internet, or to connect at the following Link:

http://www.modbus.org/

The use of GMT deletes, or at least reduces considerably, the development time of a telecontrol application. Normally the long list of high level commands and the complete groups of addressable hardware resources is sufficient for the standard demands. If the application needs additional commands or resources, they can be directly required to grifo®.

One of the most important features of GMT is that it is a ready to use product: the user is not forced to know the used communication protocol. Thanks to the Utility programs and the libraries provided with the product, it is possible to set up, test and use the communication network in few minutes.
When the Master system inside the the telecontrol network is a PC, it can be used the numerous programs that already manages the ModBUS protocol, as the SCADA; the software development tools VisualBasic; Visual C; Delphi; etc.

The GMT package is composed by software on CD, a user documentation and a specific firmware saved on the selected card.

The most important features of GMT are below summarized:

• Management of hardware resources of GMT remote devices through high level commands, that are transferred on serial line.
• Based on asyncronous serial line.
• Selectable electric protocol among the most diffused standards:
  - RS-232
  - RS-422
  - RS-485
  - Current-Loop
• Selectable physisc protocol:
  - Baud rate from 1.200 to 38.400 Baud with Autodetection
  - Odd, Even parity or No parity, programmable through specific command
  - 1 or 2 Stop Bit, programmable through specific command
• Standard logic protocol ModBUS ASCII (7 bits for character).
• Management of all the hardware resources of the selected GMT remote device, that are:
  - Digital Input signals
  - Digital Output signals
  - Analog Input signals
  - Analog Output signals
  - Counters signals
  - Pulse width modulation (PWM) signals
  - Non volatile memories (backed SRAM and EEPROM)
  - Real Time Clock (RTC)
• It can be used either on Point to Point systems or on Master Slave networks.
• Maximum number of devices connectable on network = 240.
• When network connection is used, the GMT remote devices are always Slave.
• Implementation of the MODBUS commands suitable to solve the typical problems of industrial automation:
  - READ COIL STATUS = Reads status of the single digital outputs
  - READ INPUT STATUS = Reads status of single digital inputs
  - READ HOLDING REGISTERS = Reads management registers
  - READ INPUT REGISTERS = Reads status of digital inputs
  - FORCE SINGLE COIL = Sets status of single digital output
  - PRESET SINGLE REGISTER = Sets single management register
  - FORCE MULTIPLE COILS = Sets status of digital outputs
  - PRESET MULTIPLE REGISTERS = Sets management registers
• Management of most important MODBUS exceptions:
  - Illegal function code in the command for the Slave
  - Illegal resources address in the command for the Slave
  - Illegal data values in the command for the Slave
• Possibility to manage all the hardware resources, also through the management registers (Holding Registers).
• Resource Addresses mantained for all the GMT remote device: by using a different hardware the functionality is the same.
• Associate some resources to the device status:
  - GMT firmware version
  - Identification code of GMT remote device
  - Address of device
  - Delay for the answer
  - etc.
• Reduced Execution Time: many of the received commands is executed in less than 50 µsec.
• Long list of communication Programs for PC, either under the form of Library, DLL, OCX, etc., or complete programs. These can be developed and supplied directly by grifo® or other different companies.
• Powerfull and complete Demo Program that Configures the GMT remote devices and then allows the managements of all the available resources.
• Wide Documentation and rich list of Examples both in Source and Executable format.
• It has No License nor additional costs. The user is free to develop all the applications that he requires.

- At least one GMT remote device.
- A Master system, capable to communicate with ModBUS ASCII, through a serial line equal to those available on remote device.
- Serial cable.

The use of GMT in conjunction with its commands and the remote devices resources, allows to perform the following functions:

For further information please refer to proper GMT user's manual.

	GMT 518 grifo® ModBUS Telecontrol with GMM 518
	GMT GM1 grifo® ModBUS Telecontrol with CAN GM1
	GMT H844-518 grifo® ModBUS Telecontrol H844 with GMM 518
	GMT ACB grifo® ModBUS Telecontrol with GMM ACB
	GMT HACB grifo® ModBUS Telecontrol with GMM ACB
	GMT HGM1 grifo® ModBUS Telecontrol with CAN GM1

House Automation Example. Connection of Sensors and Actuators.

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