Modbus Protocol And Com Port Configuration - Teledyne T750 User Manual

MODBUS P
5.4.
ROTOCOL AND
The following set of instructions assumes that the user is familiar with MODBUS
communications, and provides minimal information to get started. For additional
instruction, please refer to the Teledyne API MODBUS manual, PN 06276. Also refer to
www.modbus.org for MODBUS communication protocols.
Minimum Requirements
• Instrument firmware with MODBUS capabilities installed
MODBUS-compatible software (TAPI uses MODBUS Poll for testing; see
•
www.modbustools.com)
• Personal computer with communications cable (Ethernet or USB or RS232)
Possibly a null modem adapter or cable
•
MODBUS communications can be configured for transmission over Ethernet or serial
COM port through the Setup>Comm menu. Make the appropriate cable connections
(Ethernet or COM port) between the instrument and a PC.
Ethernet
Serial COM Both COM1 (labeled "RS232") and COM2 are configurable for RS-232 or
Important
Important
Next, for the settings to take effect, power off the instrument, wait 5 seconds, and power it
on again.
083730750B DCN8606
C P
OM ORT
MODBUS is available on TCP Port2 with the default number, 502, which
can be checked through the Setup>Comm> TCP Port2 menu.
RS-485 communication with either MODBUS RTU or MODBUS ASCII
transmission modes. In the Setup>Comm COM1[COM2] menu, edit the
Protocol parameter to select a MODBUS transmission mode; edit Baud
Rate, Parity, Data Bits, etc., if necessary (see descriptions in Table 3-5).
Press the Accept button to apply the settings.
When using MODBUS RTU, ensure that the COM1[COM2]
Handshaking Mode is set to either Hardware or OFF. Do
NOT set it to Software.
When more than one instrument is connected to the
network, create a unique identification number for each in
the Setup>Vars>Instrument ID menu.
C
ONFIGURATION
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