Tescom ER3000 - ER3000 Internal Variables; Setpoint and Feedback Variables; Configuration Variables

44 ER3000 User Manual
9. ER3000 INTERNAL VARIABLES
The ER3000 has a number of internal variables which can be accessed via the
RS485 interface. The most commonly used variables are listed below. The
variable index number, name, and description are shown. The index number is
the value that is entered in the DOS-based ERTALK program or the Read/Write
Screen of the Windows-based ER3000 (CVI) program to access the specified
variable. A complete list of internal variables is shown in the table at the end of
this section.
9.1 Setpoint and Feedback Variables
37 ID_SETPOINT - This is the controller’s setpoint.
43 ID_SETPOINT_FLAG - This variable determines the source of the
setpoint, variable 37 (ID_SETPOINT).
0 => setpoint from A/D, analog setpoint input
1 => setpoint from RS485 network, typically a PC.
2 => setpoint from internal pressure profile
44 ID_FEEDBACK - This is the controller’s overall feedback signal. For
internal sensor mode it is the same as inner feedback. For external
sensor mode or cascade mode it equals the outer loop feedback.
87 ID_EXT_FEEDBACK_SOURCE - This variable determines the source
of the external feedback.
0 => feedback from the compensated external sensor, see variable 5.
1 => feedback from extra analog input 1, see variable 77.
Note: For both setpoint and feedback a value of 400 counts is 0% and 3700
counts is 100%. To convert between counts and percent, use the following
formulas:
value_percent = (value_counts - 400 ) * 100 / 3300.
value_counts = ( value_percent * 3300 /100) + 400.
9.2 Configuration Variables
9 ID_CONTROL_MODE - This variable establishes the co
ntrol mode for the
controller. A value of four only occurs when a failsafe condition exists due
to a failsafe limit being exceeded (see variables 54 to 64). A value of five
only occurs if the controller is in ESTOP, emergency stop, mode.
0 => internal feedback mode.
1 => external feedback mode.
2 => cascade mode.
3 => manual mode.
setpoint = 0x08fa => inlet open
setpoint = 0x0800 => solenoids closed
setpoint = 0x0706 => exhaust open
4 => failsafe mode (read only)
5 => emergency stop (read only)