HELIX GRANVILLE-PHILLIPS Convectron ATM, Instruction Manual

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RS–485 Module Operation
Convectron
®
ATM Vacuum Gauge Module Instruction Manual
43
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4.3 RS–485 commands
RS–485 commands require entry of integer values, hex code values (such as
“0F”), values in engineering notation (such as “2.00E+02”), and
alphanumeric character strings. The
↵
symbol at the end of the command
represents the carriage return (CR), which is entered as hex code 0D or by
simultaneously pressing the “Control” and “M” keys.
Table 4-4 explains the RS–485 command structure.
Error response from
module
If a command cannot be processed, the module will send one of the
following error responses:
• COMM ER
• NVRAM ER
• RANGE ER
• SYNTX ER
See page 66 to troubleshoot the error response.
Parity
The example set parity (SP) command sequence sets parity at seven data
bits, odd parity:
Example SP command from host: #01SPO
↵
Response from module: *01 PROGM OK
↵
• An SPO command sets parity at seven data bits, odd parity.
• An SPE command sets parity at seven data bits, even parity.
• An SPN command sets parity at eight data bits, no parity. This is the
default parity.
Table 4-4 RS–485 command structure
Address field Command field Data field Carriage return
#XX Character string for
command from host Character string data required to
execute command
↵
“XX” is 2-digit address First character is:
• PC = process control
• S = set
• T = calibrate
• R = read Data may include:
• Hex code
• Pressure value in engineering
notation
• Alphanumeric character string
• Enter hex code “0D”
• Simultaneously press
“Control” and “M” keys