Watlow CAS - Manual (Page 80)

70 CAS User’s Guide
Troubleshooting
Digital Output Test
Test digital outputs this way:
1. Connect a 500 ohm to 100 Kohm resistor between the +5V pin
(TB-50 screw terminal 1) and the output pin you want to test.
2. Connect the Common lead to the output pin.
3. Connect the voltmeter positive lead to the +5V pin.
4. If you are testing a digital output, use the Manual I/O Test menu to
turn the output on and off. (See Chapter 4: Setup for information on
the Manual I/O Test menu.)
Digital Input Test
Test digital inputs this way:
1. Go to the digital input test menu (under the Manual I/O Test main
menu). This menu shows whether the digital inputs are H (high, or
open) or L (Low, or closed).
2. Attach a wire to the terminal of the digital input you want to test.
• When the wire is connected only to the digital input terminal,
the digital input test menu should show that the input is H
(High, or open).
• When you connect the wire to logic ground (TB-50 pin 3), the
digital input test menu should show that the input is L (Low,
or closed).