Watlow CLS200 - Manual (Page 145)

CLS200 Series User’s Guide Chapter 6: Enhanced Features
Doc.# 0600-3050-2000 Watlow Anafaze 129
Remote Analog Setpoint
The remote analog setpoint is set up identically to ratio
control. To provide a setpoint remotely, typically a voltage
or current source is connected to an analog input on the
controller. This input is configured as a linear input type
and the master loop for ratio control. All other input types
are also usable as remote analog setpoint inputs.
Specify the loop to which the analog input is connected as
the master loop and setup the rest of the ratio control pa-
rameters as outlined in Setup Loop Ratio Control Menu on
page 125.
Remote Analog Setpoint Example: Setting a Setpoint with a PLC
Remote analog setpoint allows external equipment, such as
a PLC or other control system, to change the setpoint of a
loop.
Both the remote analog setpoint feature and the process
variable retransmit feature can be used with PLC systems
as the link between multiloop PID control systems and
PLC systems.
For example, a 0 to 5 V Î (dc) signal representing 0 to 300˚
F will be used as a remote setpoint input to the CLS200.
The input signal will be received on loop 1 with the control
being performed on loop 2. Note that proper scaling resis-
tors must be installed on the input of loop 1 to allow it to
accept a 0 to 5 V
Î (dc) input.
To set up this application, you would do the following:
1. In the loop 1 SETUP LOOP INPUT menu, set the INPUT
TYPE to LINEAR, set HI PV to 300, set LO PV to 0, set
HI RDG to 100.0% and set LO RDG to 0.0%.
2. Change the display to loop 2, and then enter the setup
parameters. Go to the first screen in Table 6.4.
3. Follow the steps in Table 6.4 to configure the process
variable retransmit option.