Watlow 8LS Controller - Manual (Page 31)

Installation
8LS User’s Guide 23
Voltage Inputs
DC Voltage inputs should be connected with the positive side to the
High terminal and the negative side to the Low terminal. The input
range is -10 to +60 mV. Signals greater than 60 mv must be scaled with
resistors to match the input full scale to 60 mv. The scaling resistor RA
is selected as the voltage dropping and/or current limiting resistor. RB is
selected for the 60 mv full scale dropping resistor. It should normally be
less then 300
Ω and no greater then 1000Ω. Any value above 1000Ω for
RB will cause error due to the upscale burnout circuit.
This table shows scaling resistors values.
The above values are .1% standard metal film resistor values and will
give an accuracy of +0.25%. The above values at .1% are our factory
stock. Any possible error due to resistor tolerance error may be
corrected by using the built in linear scaling. Remove the jumper in the
RA location to install RA.
Milliamp Inputs
Current inputs from transmitters are accommodated by placing resistors
in the input section to convert the current input into a voltage. Different
current input ranges are accommodated by selecting the proper resistor
values.
A single 0.1% resistor is used as follows:
4 to 20 ma 0 to 10 ma
RB = 3.000
Ω RB = 6.000 Ω
Thermocouple Inputs
All thermocouple types may be directly connected to the Watlow
Anafaze 8LS. Types J, K, T, R, S, B, and N linearization and cold
junction compensation are provided standard in the Watlow Anafaze
8LS. For other thermocouple types, optional input ranges are required.
Thermocouples should be connected with the positive lead to Ana In +
terminal and the negative lead to Ana In- terminal of TB1. RA is the
only resistor used for T/C inputs and it is a jumper.
Output
Voltage Range
RA RB Accuracy
0-100 mV 499
Ω
750
Ω
+ .1 %
0-500 mV 5.49 K
Ω
750
Ω
+ .1 %
0-1 V 6.91 K
Ω
442
Ω
+ .2 %
0-5 V 39.2 K
Ω
475
Ω
- .2 %
0-10 V 49.9 K
Ω
301
Ω
- .1 %