Rs485 Serial Communications; Device Specific Serial Communication Info - Instrutech Hornet User Manual

Instruction Manual

RS485 serial communications

8
8.1

Device Specific Serial Communication Info

The standard IGM401 model provides RS485 serial communications. The following information and the RS485
command protocol summary listed on the next page can be used to establish serial communications with the
device.
1. Default settings are 19,200 baud rate, 8 data bits, No Parity, 1 stop bit [Factory default; 19,200, 8, N, 1].
2. The baud rate can be set to different values using the front panel soft-keys.
3. Minimum interval between commands sent out over the RS485 bus is 50 msec.
4. The stop bit is always 1.
5. All Responses are 13 characters long.
6. 'xx' is the address of the device (00 thru FF).
7. <CR> is a carriage return, a non-printable character. Do not enter <CR> from your keyboard. A carriage
return, non-printable character may be entered as the Unicode C0 controls specified value: 0D hexadecimal
(13 decimal). From your keyboard, a key entry sequence of CNTL-M may be used to obtain the required
character for a carriage return when using certain terminal emulator programs.
8. '_' represents a 'space' character. Press the space bar on your keyboard. Do not enter a '_'
(underscore) character.
9. The 'z' in the set or read trip point commands is a plus (+) or minus (-). The plus (+) is the 'turns on
below' setpoint and the minus (-) is the 'turns off above' setpoint.
10. All commands sent to the module start with a '#' character, and all normal responses from the module
start with a '*' character. Error responses start with a "?".
11. A valid address must be used [Factory default = 1]. The IGM401 will not respond to a command with an
invalid address.
12. The command syntax examples used in the protocol summary table for ASCII are shown in scientific
notation. However, floating point notation is acceptable as long as a leading digit is entered as '0.' or
'1.', etc. There must be a digit to the left of the decimal point. For example, when constructing the
syntax for the command to set the CGn zero value (e.g., #xxTZn_x.xxE-pp<CR> when using scientific
notation), use either #xxTZn_0.00<CR>, or #xxTZn_0<CR>. A simple '0' is valid for the pressure entry.
InstruTech, Inc.
IGM401 Hornet
Page 31