Watlow Series D8 - Manual (Page 186)

Chapter 7: Troubleshooting and Reconfiguring Series D8 User’s Guide
168 Watlow Anafaze Doc. 0600-3120-2000
• Eliminate possible ground loops. See Ground Loops on
page 22.
• Contact your supplier for further troubleshooting guid-
ance.
Testing Control Output Devices
Connect the solid-state relay (SSR) control terminals to the
D8 control output and connect a light bulb (or other load that
can easily be verified) to be switched by the SSR's outputs.
Put the loop in manual mode and set the output to 100 percent.
The ac load should turn on.
Do not attempt to measure ac voltage at the output terminals
of the SSR. Without a load connected, the SSR output termi-
nals do not turn off. This makes it difficult to determine
whether the SSR is actually working. Measure the voltage
across a load or use a load that can be visually verified, such
as a light bulb.
Testing the TB18 and TB50
1. Turn on power to the controller.
2. Measure the +5 Vdc supply at the TB18 or TB50. The
voltage should be +4.75 to +5.25 Vdc:
a) Connect the voltmeter’s common lead to TB18 ter-
minal 2 or TB50 terminal 3.
b) Connect the voltmeter’s positive lead to the TB18 or
TB50 terminal 1.
Testing Control and Digital Outputs
1. Switch off power to the controller.
2. Disconnect any output wiring on the output to be tested.
3. Connect a 500
Ω to 100 k Ω resistor between the
+5V terminal (TB18 or TB50 terminal 1) and the output
terminal you want to test.
4. Connect the voltmeter’s common lead to the output ter-
minal, and connect the voltmeter’s positive lead to the
+5V terminal.
5. Restore power to the controller.
6. If you are testing a control output, turn the output on and
off by setting the loop to 100 percent and 0 percent out-
put power (see Changing the Control Mode and Output
Power on page 85). When the output is off (0 percent),
the output voltage should be less than 1V. When the out-