Watlow Series 988 - Manual (Page 127)

WATLOW Series 988 User’s Manual 8.11 General Software Features, Chapter 8
General Software
Sample Application
The Series 988 controls the lower platen of a compression molding press
that contains five, 10-ampere heaters. A 50A:50mA current transformer is
used to monitor heater current.
Set the Input 2 prompt [`In2] to current [Curr], the Range Low 2 prompt
[`rL2] to 0 and the Range High 2 prompt [`rH2] to 50. Find the range
high 2 value with the following equation:
range high 2 = (maximum CT primary current (load current)) x 50mA
(maximum output from CT secondary (input))
The application uses a Watlow current transformer (CT) part# 16-0233,
which has a maximum input of 50 amperes, which corresponds to a maxi-
mum output of 50mA.
range high 2 = (50Amps) x 50mA
50mA
Solving for rH2 gives you 50. This is the range high 2 setting.
Figure 8.11 -
Compression mold-
ing press using the
heater current fea-
ture.
TL TL W WA
PROCESS
L1 L2 L3 L4
DEV
% OUT DISPLAY
MODE
AUTO
MAN
SERIES 988
input 1
input 2
output 1
current
transformer
limit
limit
sensor
Compre s s ion Molding P re s s
10A heaters
temperature
sensor
10A SSR
SSR-240-10A-DC1