Yokogawa RAMC - Manual (Page 65)

<8. SERVICE>
8-1
IM 01R01B02-00E-E 10th edition January 01, 2013 -00 All Rights Reserved. Copyright © 2003, Rota Yokogawa
8. Service
8.1.1 Function test
Checking free movement of pointer:
- Remove housing cover (4 screws on housing type 66).
- After deflecting the pointer by hand, it must return to measurement value. If the pointer pivots to different
values upon repeated deflections, there is too much friction in the bearings. In this case, send indication unit
to service.
Checking free movement of float:
- First, free movement of pointer has to be ascertained.
- Check visually if pointer follows each flow rate change. If not, clean float and measuring tube.
Unit with electronic transmitter:
- The display must show values corresponding to indication function and measuring unit settings.
- The bars under the 8 digits must not flash. If an error occurs, the corresponding countermeasure (refer to
chapter 6.2.8 error messages) has to be taken or the unit has to be sent to service.
- Without flow, the output current must be 0 or 4 mA. At a flow rate of 100% the current must be 20 mA.
Additional function test for HART
®
units (-H)
- check HART
®
communication using a HART
®
Handheld terminal or a PC with HART
®
communication
software.
- Setting: Device setup / Process variables
- PV AO shows the current value that should be delivered at output – Check this value using a multimeter.
8.1.2 Measuring tube, float
The RAMC is maintenance-free. If contamination of the measuring tube impairs the mobility of the float, the tube
and the float have to be cleaned. To do this, the RAMC has to be removed from the pipe.
Replacement or cleaning of the float:
- Remove RAMC from the pipe.
- Remove upper retainer from metering tube.
- Take float stopper and float out through the top of metering tube.
- Clean float and metering cone
- Insert float and float stopper into the metering tube.
- Set retainer into tube.
- Check float for free movement.
- Install RAMC to the pipe.
Attention: Do not expose float to strong alternating magnetic fields. The float and especially its measuring
edge must not be damaged.
8.1 Maintenance