Flowserve MX-100 Field Unit - Manual (Page 48)

MX/DDC-100 Field Unit Installation and Maintenance FCD LMENIM2329-01 – 03/11
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Troubleshooting
1. Refer to Appendix A, Wiring Diagram.
2. With power off and network disconnected, verify continuity between A1, A2 and A1*, A2*.
3. With power applied and network disconnected, verify 0.2 to 0.45 VDC between A1, A1* and A2, A2*.
4. Confirm that a jumper cable is installed between the grounding lug and terminal 3.
5. Verify proper setup for MX/DDC.
MPC (modulating position control) must be OFF. •
ESD must be configured for desired function and properly wired. •
OPEN INHIBIT must be configured for desired function and properly wired. •
CLOSE INHIBIT must be configured for desired function and properly wired. •
Remote four-wire control is not selected if not in use, or properly wired if selected. •
6. Confirm there are no duplicate DDC addresses.
7. Confirm that each network segment is grounded at one end only.
8. Confirm protocol, baud rate
example: Field Unit 1 - 9600, Modbus, RTU, 8,1,N
Field Unit 2 - 9600, Modbus, ASCII, 8,1,N
Confirm error and correct
Field Unit N - 9600, Modbus, RTU, 8,1,N
9. Confirm that host controller allows sufficient timeout periods (at least 200 ms).
Confirm that host controller allows at least one message retry before declaring loss of communication.
10. Main power supply must be within +/-10% of nominal unit power rating at all times. Refer to nameplate for
voltage.
11. UPS of 24 VDC must be within +/-10% at all times.
12. Workmanship:
The MX is non-intrusive which facilitates ease of configuration without removal of the controls cover. Removal •
of the controls cover without permission from Flowserve can void the warranty.
Practice all plant and safety codes and standards. Failure to follow instructions can result in personal injury
•
and/or property damage.
Do NOT remove covers of Division 1 units with power applied to prevent the possible ignition of hazardous
•
atmospheres.
All servicing should be performed by qualified technicians. Dangerous voltages may be present on the circuit
•
boards and terminations.
Use extreme caution when working around power input cables. These cables have potentially lethal voltages on
•
them.
Replace fuses only with specified parts for continued safe operation.
•
Have qualified personnel verify all wiring and connections against vendor drawings prior to energizing the •
equipment. Incorrect wiring and/or connections can result in equipment damage.
NOTE: Removal of control cover and replacement of control boards must be performed by authorized Flowserve
Limitorque service personnel only. Consult a Flowserve Limitorque service coordinator at (434) 528-4400.
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