Installation, Operation & Maintenance Parksafe Gas Detector
Rev: 9 10-20
6
Wiring your Detector
Power and Modbus data are wired between detectors with the first
connected to a control panel DETECTOR CHAIN terminal.
For MODBUS communications, a shielded cable is used.
The shielding can be of 2 types: braided [mesh of thin conducting
wires] or foil (consisting of a thin sheet of metal covering the
twisted wires).
One example of such cable is BELDEN 3082A.
If you are encountering noise or irregular problems with a Modbus link, the problem is likely related to
grounding, incorrect shielding or wiring mains power next to Modbus wiring.
To ground the data cable, the shield should be connected to [-] of the chain terminals.
Reversing the [D+] and [D-] connections of any device can lead to the whole system to stop working
owing to reverse polarity found on the terminals.
Not appropriately grounding the device can give false readings, fail completely or turn into a safety
hazard!
Detector Chain ID Switches
When wiring multiple detectors in a chain it is important to identify each and every
detector installed for the control panel to receive and display accurate Modbus
data corresponding with the correct detector type.
The ID configuration diagram is printed onto detector boards for quick
reference. All detectors are factory set to ID1.
ID Switches must be configured for each and every detector connected to a
system to receive and display accurate data!
We recommend a plan, map and/or marking the detector enclosures detailing ID and location!
