Fluke 9140 U

7.4 Temperature Display Hold

The 9140 has a display hold function which allowsaction of an external switch

to freeze the displayed temperature and stop the set-point from scanning. This

is useful for testing thermal switches and cutouts. This section explainsthe

functions availablefor operating the temperature hold feature. An example fol-

lows showing howto set up and use the hold feature to test a switch.

7.4.1 Hold Temperature Display

The hold feature is enabled by simply pressing the “UP” button.The hold tem-

perature display shows the hold temperature on the rightand theswitch status

on the left. For the status “c” means the switch is closed and “o” means the

switch is open. The status flashes when the switch is in its active position (op-

posite the normal position). The hold temperature showsw hatthe temperature

of the well was when the switch changed from its normal position to its active

position. While the switch is in the normal position the hold temperature will

follow the well temperature. Operation of the hold temperaturedisplay is out-

lined below.

143.5 C Well temperature display

UAccess hold display

c 144.8 Switch status and hold temperature

Toreturn to the normal well temperature display press “DOWN”.

7.4.2 Mode Setting

The Hold Function is always in the automatic mode. In thismode the normal

position is set to whatever the switch position is when the set-point is changed.

For example, if theswitch is currently open when the set-point is changed, the

closed position then becomes the new active position. The normal position is

set automatically under any of the following conditions, (1) a new set-point

number is selected, (2) the set-point value is changed, (3) a newset-point is set

through the communications channels.

The operating mode of the temperature hold is set in the primary menu after the

scan rate setting.

7.4.3 Switch Wiring

The thermal switch or cutout is wired to the calibrator at the two terminals in

the front of the dry-well calibrator labeled “SWITCH HOLD”. The switch

wires may be connected to the terminals either way. Internally the black termi-

nal connects to ground. The red terminal connects to +5V through a100 k Ωre-

25

7 Controller Operation

Temperature Display Hold

Contents

Main Page Table of Contents 8 Digital Communication Interface . . . . . . . . . . . . . . . . 33 9 Test Probe Calibration . . . . . . . . . . . . . . . . . . . . . . 39 Page Figures Page 1 Before You Start 1.1 Symbols Used Table1 lists the symbols used on the instrument or in this manual and the meaning of each symbol. 1.2 Safety Information 1.2.1 WARNINGS Page 1.2.2 CAUTIONS 1.3 Authorized Service Centers Page 2 Introduction 3 Specifications and Environmental Conditions 3.1 Specifications 3.2 Environmental Conditions 9 3 Specifications and Environmental Conditions Specifications 3.3 Warranty 4 Quick Start 4.1 Unpacking 4.2 Set-Up 4.3 Power 4.4 Setting the Temperature 5 Parts and Controls 5.1 Rear Panel 5.2 Front Panel 5.3 Constant Temperature Block Assembly 5.3.1 Constant Temperature Block 5.3.2 Probe Sleeves and Tongs Page 6 General Operation 6.1 Calibrator Set-Up 6.2 Changing Display Units Un= C 6.3 Switching to 230 V Operation 6.4 Setting the Temperature 6.5 Calibrating Probes Page 7 Controller Operation 7.1 Well Temperature 100.0 C 7.2 Temperature Set-point 7.2.1 Programmable Set-points Page S 7.3 Scan S 7.4 Temperature Display Hold 7.4.1 Hold Temperature Display 143.5 C U c 144.8 7.4.2 Mode Setting 7.4.3 Switch Wiring 7.4.4 Switch Test Example 7.5 Secondary Menu 7.5.1 Heater Power 100.0 C S+EAccess heater power in secondary menu SEC 12.0P 7.5.2 Proportional Band S+EAccess heater power in secondary menu SEC S 12.0P S 7.6 Controller Configuration 7.6.1 Calibration Parameters CAL 7.7 Operating Parameters PAr 7.8 Serial Interface Parameters SErIAL bAUd Page Page 8 Digital Communication Interface 8.1 Serial Communications 8.1.1 Wiring 8.1.2 Setup 8.1.3 Serial Operation 8.2 Interface Commands Users Guide Tabl e 2 9140 controller communications commands 36 37 8 Digital Communication Interface Interface Commands Tabl e 3 9140 controller communications commands continued 9 Test Probe Calibration 9.1 Comparison Methods 9.1.1 Calibrating a Single Probe 9.1.2 Comparison Calibration 9.1.3 Calibration of Multiple Probes 9.2 Dry-well Characteristics 9.2.1 Vertical Gradient 9.2.2 Heating and Cooling Rates WARNING:DO NOT remove inserts when heating or when the unit is hot. 9.2.3 Stabilization and Accuracy Figure 8 Typical Cooling Rate 41 9 Test Probe Calibration Dry-well Characteristics BlockTemperature C Page 10 Calibration Procedure 10.1 Calibration Points 10.2 Calibration Procedure 10.2.1 Compute DELTA: 10.2.2 Compute R0& ALPHA: 10.2.3 Accuracy & Repeatability 11 Maintenance 12 Troubleshooting 12.1 Troubleshooting Problems, Possible Causes, and Solutions 12.2 CE Comments 12.2.1 EMC Directive 50 12.2.2 Low Voltage Directive (Safety) Users Guide