Page 68 - GuardII+ Series 4208 Platform Flux User Manual

Appendix

NOTE:
If the measurement status is consistently showing a value other than “2”,
this may indicate a problem. Refer to Section 7 for troubleshooting
instructions and/or consult Iris Power LP Technical Support for assistance.

For round-rotor machines, coils with more than 10 turns per coil typically show signs of a
problem when the coil-to-coil flux density differs by 3%. Round-rotor machine coils with less
than 10 turns per coil typically show signs of a problem when the coil-to-coil flux density differs
by 5% to 10%. For salient-pole machines, poles typically show signs of a problem when the
th
pole-to-pole flux density differs by 1% to 2%. Flux density is reported in 100 ’s of a percent;
so a value of -300 reported on Modbus on a salient-pole machine indicates a flux density drop
of 3%, and therefore a potential problem.

8.4. Modbus Slave Timing

NOTE:
As described in Section 4.2, GuardII+ updates the flux Modbus data
registers after every measurement cycle, which occurs every 30 minutes.;
so while the monitor can respond to Modbus requests very quickly, the
flux data simply will not change that often. Polling the monitor every few
seconds is just wasting network bandwidth.
Each monitoring technology in the GuardII+ Series 4208 Platform has its
own measurement cycle; so If the monitor has other monitoring
technologies installed, those other technologies may provide Modbus
updates more rapidly.

To achieve the best performance when polling GuardII+’s Modbus data registers, the
following configurations of the polling system should be used:
• Modbus response timeout should be set to no less than 6000ms

• Modbus polling should occur no more often than once per minute.

8.5. Using PLC-Style Addressing

GuardII+ uses protocol-style Modbus addressing (Base 0), not PLC-style Modbus
addressing (Base 1). When using PLC-style addressing to acquire Modbus data from
GuardII+, this will cause an address shift.
NOTE:
When accessing GuardII+ data registers using PLC-style addressing, the
address must be increased by 1.

Sample Addresses using Modbus (Base 0) Addressing
Address Data Notes
6000 Year The year of the last measurement
Expressed in 4 digits (i.e., 2019)

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