Watlow CAS200 - Manual (Page 94)

Chapter 5: Troubleshooting and Reconfiguring CAS200 User’s Guide
82 Watlow Anafaze
You will need tweezers and a Phillips head screwdriver to
switch between EIA/TIA-232 and EIA/TIA-485. Follow
these steps:
1. Power down the unit.
2. Remove the scanner’s metal casing. See Replacing the
EPROM on page 79 for step-by-step instructions.
3. Find jumpers JU2, JU3, JU4, and JU5 on the board.
4. Use tweezers to carefully grasp the jumpers and gen-
tly slide them off the pins.
5. Use tweezers to gently slide jumpers JU2, JU3, JU4
and JU5 onto the correct pins (see Figure 5.5).
6. If you are configuring the scanner as the last device on
an EIA/TIA-485 network, move JU1 to the B position.
7. Reassemble the scanner.
Installing Scaling Resistors
Resistors are installed for all inputs on the CAS200. Inputs
with signal ranges between -10 and +60mV use 0
Ω
resistors in the RC position only. All other input signals
require special input scaling resistors.
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CAUTION! Scaling resistors are soldered to the circuit
board. Only qualified technicians should attempt
to install or remove these components. Improper
techniques, tools or materials can result in dam-
age to the scanner that is not covered by the war-
ranty.
CAS200 Input Circuit
The CAS200 can accept single-ended thermocouple, mVdc,
Vdc and mA dc inputs. Unless ordered with special inputs,
the scanner accepts only signals within the standard range
-10 to 60 mVdc.
To accommodate other signals, the input circuit must be
modified. When configured for thermocouple inputs, 0
Ω
resistors are installed in all RC locations. To accommodate
milliamp current signals or voltage signals outside the
standard range, resistors are added or replaced to scale the
signals to the standard range. These resistor can be
installed by Watlow Anafaze or by a qualified electronics
technician using scaling resistors supplied by Watlow
Anafaze.