Alpha Omega Instruments 800 Series User Manual

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MODBUS COMMAND SYNTAX
These are the two commands used to read and write to the Series 850 TEC Conttroller
via GPIB.
The reg number for the variable to read can be found in the MODBUS register table on
page 110.
WARNING
Writing continuously to any register within a program loop can cause premature failure
of the EEPROM inside the controller.
Only write to a register after first reading it to check whether or not it should be changed.
Please see Appendix K on page 102 for more information on how to avoid this.
Notes
Write Register Command. Writes a 16 bit value, w to a single Modbus device register,
reg. Values for reg are 0 to 32767. Values for w are 0 to 65535.
Example:
W 100,55 writes the decimal value 55 to register 100 (process temperature).
Meaning
W reg, w
The reg number for the variable to read can be found in the MODBUS register table on
page 110.
Notes
Read Register Command. Reads one or multiple Modbus device registers. User
specifies starting register reg and number of registers to be read num. The [?] is an
optional symbol. Values for reg are 0 to 32767. Values for num are 1 to 64. Responses
are returned as 16 bit decimal or HEX values separated by commas. Output format
selected with the Format command.
Examples:
R? 300,1 reads the set point
R? 100,1 reads the actual process temperature.
R? 713,3 reads the current limit registers 713, 714, & 715.
R[?] reg, num
MeaningSyntax
ALPHA OMEGA INSTRUMENTS CORP. Instruction Manual
Series 800/850 Thermoelectric Cooler Controller Page 86

Alpha Omega Instruments 800 Series Specifications

General

Brand	Alpha Omega Instruments
Model	800 Series
Category	Controller
Language	English