Watlow Series 982 - Manual (Page 127)

WATLOW Series 982 User’s Manual 9.13 Software Features, Chapter 9
Software
Sample Applications
An engineer needs to control the temperature of individual zones in an
eight-zone furnace. The temperatures range from 0°C to 850°C. The
process requires the same time/temperature profile for each zone. She
wants to do this without using a seperate ramping control for each zone.
The Series 982 can be configured with a milliamp retransmit output for
output 3, (98_C-____-M___). This controller can control one zone and pro-
vide a common 4-20 mA set-point signal for seven Series 988 controllers
with remote-set-point capabilities.
Enable the retransmit output by setting [Aout] to [StPt] (Output Menu).
This selects the set point as the retransmit variable. To select the retrans-
mit output range, set [Prc3] to [4-20]. The retransmit output is now 4-
20mA. [`ArL] and [`ArH] determine the scaling for the retransmit output.
To make a 4mA signal represent 0°, set [`ArL] to [```0]. To make a 20mA
signal represent 850°, set [`ArH] to [`850]. A retransmit calibration offset
[ACAL] is also available, which applies only to the retransmit output.
The retransmit output will be 4mA until the set point is greater than 0°C
and will increase linearly until reaching 20mA, when the set point equals
850°C. The output will not exceed 20mA.
As the Series 982 changes its set point, the 4-20mA retransmit signal fol-
lows it, providing the remote set point signal for the seven Series 988 con-
trollers.
The furnace now can provide ramp and soak capabilities for all eight
zones, yet reduce system costs and complexity by using a single ramping
controller and seven remote-set-point controllers.
TL TL W WA
PROCESS
L1 L2 L3 L4 DEV % OUT DISPLAY
MODE
AUTO MAN
SERIES 988
TL TL W WA
PROCESS
L1 L2 L3 L4 DEV % OUT DISPLAY
MODE
AUTO MAN
SERIES 988
TL TL W WA
PROCESS
L1 L2 L3 L4 DEV % OUT DISPLAY
MODE
AUTO MAN
SERIES 988
TL TL W WA
PROCESS
L1 L2 L3 L4 DEV % OUT DISPLAY
MODE
AUTO MAN
SERIES 988
TL TL W WA
PROCESS
L1 L2 L3 L4 DEV % OUT DISPLAY
MODE
AUTO MAN
SERIES 988
TL TL W WA
PROCESS
L1 L2 L3 L4 DEV % OUT DISPLAY
MODE
AUTO MAN
SERIES 988
TL TL W WA
PROCESS
L1 L2 L3 L4 DEV % OUT DISPLAY
MODE
AUTO MAN
SERIES 988
zone 1
Ma s t e r
output 3
zone 2
Re mot e
input 2
zone 3
Re mot e
input 2
zone 4
Re mot e
input 2
zone 5
Re mot e
input 2
zone 6
Re mot e
input 2
zone 7
Re mot e
input 2
zone 8
Re mot e
input 2
TL TL W WA
PROCESS
L1 L2 L3 L4 DEV
% OUT DISPLAY
SERIES 982
MODE
HOLD RUN
Figure 9.13 -
Heat-treat oven with
retransmit.