envea STACK 602, User Manual

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STACK 602 9 Maintenance
ENVEA UK Ltd
(PC-000848-MA Issue 5, December 2021)
vii
Solution: if the problem exists with one or two devices, visit those devices
and check:
4. Cable connections
5. Comms DIP switch settings
6. Network address DIP switch settings
7. Bus termination setting.
NOTE
: To prevent bus conflicts, each sensor/device must have a unique address. Devices
must not use address ‘0’.
9.5.2 Checking Spurs
Where network spurs are used, the internal yellow and green LED’s may be used
as a service guide. The devices communicate by a set of query–response cycles.
If either LED is stuck on, this indicates a wiring error or possibly an incorrectly set
bus termination switch at some point in the network.
9.5.3 Sensor Power Check
Each sensor has a green LED located in the Receiver (LD200) that flashes at
approx. 1Hz (with equal spacing: 0.5s ON, 0.5s OFF). When power is correctly
applied to the sensor (before the control unit is ready to communicate with the
sensor).
If the LED is OFF, check the connections to the sensor and measure the network
supply voltage (between the black and red cores).
9.5.4 Sensor Communications Check
When the control unit communicates with the sensor, and the sensor has accepted
the control unit data and decided that it is a valid command, the operation of the
red LED changes: it flashes briefly (approx. 50–100ms) every time it receives a
valid command from the control unit. If the control unit commands cease, the
sensor waits 4 seconds (LED OFF), then reverts to the 0.5s ON/OFF mode of
operation.
9.5.5 Power Loss
The sensors are powered from the control unit (24V DC). With long cable runs,
there will be voltage drop along the cable. If the voltage drop is too large (<18V),
the sensor will not communicate correctly. Check the voltage at each sensor with
a multimeter between the 24V and 0V pins.
NOTE
: Voltage drop – if the voltage is too low at any sensor in the network, this may cause
comms problems throughout the network. Correct voltage problems by adding a PSU
Repeater to the network. If you are already using a PSU Repeater, check that it has
not been powered OFF.