Raven Industries SCS 450 - Manual (Page 50)

Chapter 7
46 SCS 450 Serial Interface Installation & Service Manual
Speed Sensor Cables
Testing Speed Sensor Extension Cables
Note:
Verify that the console is in the SP1 Speed Sensor mode while testing the cable.
1. Disconnect the extension cable from the speed sensor assembly cable.
FIGURE 2. Speed Sensor Connector Cable Connection
Note:
If a +5 VDC voltage reading is not present, disconnect the flow sensor cable. If the speed reading
is restored, refer to the Testing Flow Meter Cables section on page 44
to test the flow meter
cables.
If the speed system is a radar-type system, the voltage between the 10 o’clock and 2 o’clock
positions may read +12 VDC.
1. Enter a SPEED CAL value of 9999 into the console.
2. Press the DISTANCE button.
3. Create a short between the ground and signal sockets by inserting a small jumper wire or paper clip into
both sockets simultaneously. Each time contact is made, the DISTANCE reading should increase in
increments of 1 or more. If the DISTANCE does not increase:
a. Remove the section of cable closest to the console.
b. Repeat the ground-signal short test.
• If the DISTANCE does not increase, replace the defective cable and repeat the ground-signal
short test.
• If the DISTANCE increases, replace the speed sensor.
4. Perform voltage checks as illustrated in the figure above.
Important: Re-enter the original SPEED CAL figure after testing is complete.
Power
Signal
Ground
+5 VDC
+5 VDC