— A B B M E A SU R EM ENT & A N A LY TI C S | S ERV I CE I NS TRUC TI O N

SMA 90Analytical instruments smart analyzer

This Service Instruction is to: Adjust the SMA O2 heater voltage to 18 V DC and must be used with the reusable SMA O2 heater voltage adjustment compulsory kit part no. 258418A2-ACC

July 2018

IntroductionFor improved performance of the O2 sensor, the O2 sensor heater voltage must be set to 18 V DC. This change is performed using the R3 potentiometer located on the input / output (I/O) circuit board.

Note. This procedure must be carried out once only at O2 sensor replacement if the change was NOT effected at a previous O2 sensor replacement.

Tools / materials required• O2 heater voltage adjustment safety shock-

shield kit from ABB (part no. 258418A2-ACC) comprising:

– Shock-shield – 2 x 10-32 x 3/8 in shock-shield securing screws – 5 inch, 20 gauge voltage measurement

extension wire – Insulated pot trimmer screwdriver

(see Figure 1) – Sticker to be affixed to the inside of SMA O2

analyzer's upper door indicating that the O2 heater voltage is set to 18 V DC

• Digital volt meter (DVM)

Figure 1 Insulated pot trimmer screwdriver

—SMA 90 smart analyzer

Service

2 S M A 9 0 | A N A LY TI C A L I NS TR U M ENTS SM A RT A N A LY ZER | S I/A N A I NS T/0 0 2- EN R E V. A

1 Health and safety

Safety precautionsBe sure to read, understand and follow the instructions contained within this document before and during use of the equipment. Failure to do so could result in bodily harm or damage to the equipment.

WARNING – BODILY INJURY This procedure must be performed:

• by suitably trained personnel only

• in accordance with relevant national and local regulations

Potential safety hazards

WARNING – BODILY INJURY• This procedure must be performed with the SMA

analyzer powered with 120 / 240 V AC.

• Do not attempt this procedure unless the O2 heater voltage adjustment safety shock-shield is fitted as detailed in this instruction.

2 Initial check

Open the SMA O2 analyzer's upper and lower doors and check if there is a sticker indicating that the system has been set to 18 V DC. Continue with this procedure only if there is no sticker.

3 Adjusting the O2 sensor heater voltage

1 Switch off power to the SMA O2 analyzer.

2 Replace the O2 sensor (part no. 258418A2) if necessary.

Note. The following steps must be performed with the O2 sensor connected.3 Open the SMA O2 analyzer's upper and lower doors.

4 Referring to Figure 2, disconnect connector block TU-P2 located in the bottom section of the enclosure.

Connector block TU-P2O2 sensor heater connectionsO2 HTR(+) and O2 HTR(–)

Figure 2 Sensor heater terminals

S M A 9 0 | A N A LY TI C A L I NS TR U M ENTS SM A RT A N A LY ZER | S I/A N A I NS T/0 0 2- EN R E V. A 3

5 Referring to Figure 3, unscrew the O2 HTR(+) and O2 HTR(-) terminals (see Figure 2) and, taking care not to disturb the existing wires, connect the voltage measurement extension wire from the kit (red to O2 HTR(+) and black to O2 HTR(-)) and tighten the terminal screws.

Voltage measurement extension wire connections

Figure 3 Connecting extension wire

6 Referring to Figure 2, reconnect connector block TU-P2.

7 Referring to Figure 4:

a. Place shock-shield A on the analyzer enclosure as shown, aligning the top and right side edges as indicated on the shock-shield.

b. Pass the extension wires through hole B in the shock-shield marked 'Extension leads to voltmeter'.

c. Insert 3 flaps C marked 'insert this flap under instrument case frame' under the lip on the left side of the enclosure as shown.

d. Secure the shock-shield to the enclosure with 2 screws D from the kit as shown.

A B

C

D

E

Figure 4 Safety shock-shield installation

8 Connect the DVM to the extension wire.

9 Restore power to the SMA O2 analyzer.

10 After power has been applied for at least 10 minutes:

a. Measure the O2 sensor heater DC voltage and record it as: VO2heater_present

Note. If the O2 sensor heater DC voltage is >18 V DC, adjustment is not necessary. Go to step 11.

b. Calculate the cable length (in feet) using the formula:Cable Length = 485 × VO2heater_present – 8250

c. Calculate the new O2 sensor heater voltage setting using the formula:

VO2heater_new = 0.0021 × Cable Length + 18.02

d. Referring to Figure 5, locate the R3 potentiometer in the top section of the O2 analyzer's enclosure.

Figure 5 R3 potentiometer location

e. Referring to Figure 4, use the recessed end of the insulated pot trimmer from the kit (see Figure 1) through hole E marked 'R3-potentiometer', to adjust the R3 potentiometer until the voltmeter measurement equals VO2heater_new.

11 Switch OFF power to the SMA O2 analyzer.

12 Disconnect the DVM and remove the shock-shield.

13 Attach the sticker from the kit to the inside of the SMA O2 analyzer's upper door to indicate that the O2 sensor heater voltage has been changed to 18 V DC.

14 Referring to Figure 2, disconnect connector block TU-P2.

15 Referring to Figure 3, unscrew the O2 HTR(+) and O2 HTR(-) terminals and remove the extension wires that were connected to connector TU-P2 in step 5, taking care not to disturb the existing wires. Tighten the terminal screws.

16 Referring to Figure 2, reconnect connector block TU-P2.

17 Close the SMA O2 analyzer's upper and lower doors.

18 Restore power to the SMA O2 analyzer.

SI/

SM

A9

0/O

2Hea

ter-

EN

RE

V. A

0

8.2

018

—ABB Limited Measurement & Analytics Oldends Lane, Stonehouse Gloucestershire, GL10 3TA UK Tel: +44 (0)1453 826661 Fax: +44 (0)1453 829671 Mail: instrumentation@gb.abb.com

ABB Inc. Measurement & Analytics 125 E. County Line Road Warminster, PA 18974 USA Tel: +1 215 674 6000 Fax: +1 215 674 7183

abb.com/measurement

—We reserve the right to make technical changes or modify the contents of this document without prior notice. With regard to purchase orders, the agreed particulars shall prevail. ABB does not accept any responsibility whatsoever for potential errors or possible lack of information in this document.

We reserve all rights in this document and in the subject matter and illustrations contained therein. Any reproduction, disclosure to third parties or utilization of its contents – in whole or in parts – is forbidden without prior written consent of ABB.

Copyright © ABB 2018All rights reserved