3030 Laura Lane, Middleton, WI 53562 800/688-4116 FAX 608/836-1736 Copyright 1994 Electronic Theatre Controls, Inc. Specifications subject to change. 9-94
Introduction Air must flow through the Sensor Control Electronics Module (CEM) at a rate of at least 50 feet per minute to ensure proper cooling and avoid rack shutdown. For this reason, the CEM contains an airflow sensor that automatically shuts the rack down any time it detects an interruption in the flow of cooling air through the rack. This airflow sensor must be properly calibrated in order to do its job. The airflow sensor calibration tool allows you to calibrate the sensor. This tool consists of a small wind tunnel with a two-speed fan and a circuit to detect and alert you when the airflow sensor trips. A properly calibrated sensor will not trip at the higher air speed and will trip at the lower speed. The sensor’s calibration potentiometer is very sensitive, and it may take several attempts between the two settings to successfully calibrate i t. The procedures outlined in this document explain how to calibrate the airflow sensor. For more information regarding the procedure, or to obtain the necessary equipment, contact ETC at 800/688-4116.
Airflow sensor calibration tool
Airflow outlet
Ribbon cable connector
ETCLink connector
Fan switch
Test button LED
Test button
CR13
K4
F5 R5 R40 C21
J13
K CR12 U27
U28
U35
U33
R 58
Y3
2 5 R
CR23
C 16 R51 C81 R53 C80
U34
4 1 R C
P3
U25
R45
C9
R14
R15
T2
˙
U24 C11 CR21
F2 R2
CR20
R3
CR19
CR17
R7
CR18
R56 C32
4 7 5
C2
C12
U42
K C10
C30
AC power connector
Outputs 1-24
Test switch
ETCLink connector (on face panel)
Airflow sensor
1 P R
C56
C33
2 6 C
U40
U14
9 5 C
U45 TP1
C34 VR4
R66
8 5 C
C35 C36
VR3
C49
C37
5 1 C
C50
5 5 C
U17
U46
J11
U49
1 C
J10
R11
U47
7 5 C
C54
R 2 1
CR27 P4
R19 R16
R68
C5
C29
F4
C47
VR1
C8 RP12
VR6
9 6 C
P6
R8
C51
CR29
8 4 C
C41
4 7 5
C6
R44
C26
J15
U38 2 7 C
U48
U44
R46
TS1
R9
CR15
S1
R1 J14
R23
U41
ELECTRONICTHEATRE CONTROLS P7
CR1 R41
2
4 7 5
RP3 VR2
P5
R67
7050B4001
4 7 5
U39 U31
R57
R10
R12
4 7 5
C 18
U30
C52
C14 F1
4 7 5
R43
R13
T1
CR26
C23
U29
R42 U23
T5
CR10
R 59
C25 F3 T3
R18 R17
U37 CR11
T4
CR22
Control Electronics Module
0 6 C
U13 J12
J16 Q1
Sensor Airflow Calibration Manual
Calibration procedure Part A You will need the following equipment: • • • • • 1.
Custom AC power cord Calibration tool Control ribbon cable ETCLink cable Jeweler’s flat screwdriver (not provided)
Plug ribbon cable into the connector on the calibration tool and outputs 1– 24 on the CEM. Be certain the side of the connector marked TOP faces up and that the red edge of the ribbon cable lines up with pin 1 on the CEM.
2. Plug one end of the ETCLink cable into the ETCLink connector on the calibration tool and the other end into the CEM’s face panel. 3.
Place the airflow outlet of the calibration tool against the airflow intake on the right side of the CEM face panel. Line up the right side of the CEM with the right side of the tool. See illustration below.
Top
Top
AC power
Outputs 1-24 Pin 1
Test – Norm
4. Attach the power cord connector to the connector labeled AC in the back left corner of the CEM. Be certain the side of the connector marked TOP faces up. 5. Set the test switch on the CEM to the TEST position. 6. Plug the power cord inot a standard wall outlet. This turns on the CEM.
Sensor Airflow Calibration Manual
3
Part B
Off Low
High CEM
Fan switch
1.
Set the fan switch (S1) on the calibration tool to the high speed setting (toward the CEM).
2.
Press and release the test button on the calibration tool. The test button LED turns off.
3.
If the test button LED relights within one minute, go to Part D . Otherwise, go to Part C .
1.
Set the fan switch (S1) on the calibration tool to the low speed setting (furthest from the CEM).
2.
If the test button LED lights within 15 seconds, go to Part E . Otherwise, go to step 3.
3.
Pry up the metal flange on the CEM airflow sensor unit.
Part C
Flange
Caution: The black center of the airflow sensor is very fragile. As you pry up the flange, take extreme care not to contact it. 4.
Use the screwdriver to turn the potentiometer inside the airflow sensor slightly clockwise.
5.
Wait 15 seconds, then press and release the test button on the calibration tool.
6.
If the test button LED lights within 15 seconds, return to Part B . Otherwise, return to step 4.
Part D Airflow sensor
1. Pry up the metal flange on the CEM airflow sensor. Caution: The black center of the airflow sensor is very fragile. As you pry up the flange, take extreme care not to contact it. 2.
Use the screwdriver to turn the potentiometer inside the airflow sensor slightly counterclockwise.
3.
Wait 15 seconds then press and release the test button on the calibration tool.
4.
If the test button LED stays off for one minute, return to Part C . Otherwise, return to step 2.
1.
The airflow sensor in the CEM is calibrated to 50 feet per minute. Unplug AC power cord from power source.
Part E 2. Disconnect all three cables from CEM. 3. Close the metal flange on the CEM airflow sensor. 4. Set test switch on CEM to the NORM position.
