Dwyer 8600 - Manual (Page 16)

949-1277-3 Page 16 December, 1998
OPERATION AND PROGRAMMING OF OPTIONS
Options 924, 926, 928, Analog Remote Set Point
The analog remote set point allows the control set point to be determined by
an outside analog signal. The signal may be 0 to 10 VDC (Option 924), 0
(or 4) to 20 mADC (Option 926), or 0 to 10,000 Ohms (Option 928).
Wire the input as shown on page 7.
To set up the analog remote set point, first determine the scale range that
the analog signal will represent. The maximum span is 11,998 degrees or
counts. In the Secure Menu set rSCL for the scale value that will be
represented by the low end of the analog signal (0 Volts, 0 mA, 0 Ohms). Set
rSCH for the scale value that will be represented by the high end of the
analog signal (10 Volts, 20 mA, 10,000 Ohms).
If you require a suppressed scale or input, you may use the following
equations to determine the proper settings for rSCL and rSCH.
K = (Highest desired scale reading - Lowest desired scale reading) /
(Maximum desired analog signal - Minimum desired analog signal).
rSCH = ((Maximum possible analog signal- Maximum desired analog signal)
* K) + Highest desired analog reading.
rSCL = Lowest desired scale reading - ((Minimum desired analog signal) * K).
Operation is simple. Make sure that a valid analog signal is available to the
control. In the Secondary Menu set the rSPt to On. The REM indicator on the
front of the control will turn on. When the control returns to the HOME position,
the displayed SV will be the value supplied from the analog remote signal. If
the analog remote signal fails or goes out of range of the SPL or SPH settings,
the control will revert to the internal SP1 (or #SP1), and flash the error message
CHEC rSPt. If SPL or SPH are set outside of rSCL or rSCH then the error will
be suppressed, and the control will attempt to work with the remote value.
To clear the error message, change rSPt to OFF.
Option 934, 936, Analog Retransmission.
The analog retransmission option allows the Process Variable or the Set
Variable to be sent as an analog signal to an external device. The signal may
be either 0 to 10 VDC (Option 936) or 0 (or 4) to 20 mADC (Option 934). The
output may be changed in the field from one to the other by the toggle switch
located on the top printed circuit board.
Wire the output as shown on page 7.