metso automation PDP 400 maxDPU4F Series, Руководство по оборудованию

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Model PDP Series 200 maxDPU4F Hardware Guide
Metso Automation
•
278705
•
8-2
maxDPU4F IRIG-B Specifications
Interface Supported: IRIG-B Amplitude Modulated (B122)
Input range (V1): 3V to 10V peak-to-peak with 0VDC offset
Modulation Ratio (V1/V2): 2:1 to 4:1 (3:1 is optimal)
Input Impedance: >10K ohms
Input connector: BNC for coaxial cable
IRIG-B Cabling
The IRIG-B input is transformer coupled within the DPU. The BNC
connector is not grounded at the DPU. To prevent ground loop problems, the
IRIG-B signal/coaxial cable should only be grounded at the IRIG source.
The IRIG-B input does not have surge or transient protection so care should
be taken to ensure that the IRIG cable is not routed through electrically
hostile (noisy) areas. Keep it away from field wires, motor wires and other
noisy signals. To reduce the likelihood of noise pickup, do not run the IRIG
cable parallel to noisy wires.
Since the IRIG input on the DPU is high impedance and the IRIG sources
have low output impedance (typically 50 or 600 ohms), the signal may be
applied in parallel to multiple DPUs via BNC “T” or “Y” connectors.
However, if that single cable is damaged, all of the parallel-wired DPUs
could lose their IRIG signal. For more redundancy in an installation use
separate outputs from the IRIG source and wire each output to only one
DPU. For even more redundancy, use more than one IRIG source with one
driving a primary DPU and the other driving the secondary.
DPU Configuration for IRIG
The TimeSync atom in the DPU4F must be configured for IRIG operation.
Configuration and operating information is contained in the time
synchronization chapter in the System Resources Guide (manual #278609).
That chapter also contains other important information on time
synchronization.