Owner manual

Troubleshooting
CLS User’s Guide 109
Checking Digital I/O
The following steps will help you test digital inputs and outputs.
TB-18 and TB-50 Test
1. Plug in the CLS power supply, if you have not already done so.
2. Measure the +5Vdc supply at your TB-18 or TB-50:
A. Connect the voltmeter's Common lead to your TB-18 screw
terminal #2 or TB-50 screw terminal #3.
B. Connect the voltmeter's Power lead to your TB-18 or TB-50
screw terminal #1. The voltage should be 4.75 to 5.25 Vdc.
Control and Digital Output Testing
1. Connect a 500 ohm to 100 Kohm resistor between the +5V pin
(TB-18 or 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 PID control output, use the Man/Auto front
panel key to turn the output on (100%) and off (0%). When the out-
put is off, the output voltage should be less than 1V. When the out-
put is on, the output voltage should be between 3.75 and 5.5V.
5. If you are testing a digital output, use the Manual I/O Test menu to
turn the output on and off. (See
Setup
for information on the Man-
ual I/O Test menu.)
Digital Input Testing
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.
A. 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).
B. When you connect the wire to logic ground (TB-18 pin #2; TB-
50 pin #3), the digital input test menu should show that the
input is L (Low, or closed).