Heater Burnout Alarm And Sensor Abnormality Alarm; Control Period: Cp - Omron E5EX–H Manual

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Table Of Contents

Table of Contents

E5EX–H

Level 1

In this level, the upper- and lower-limit values of the temperature

range, control period, hysteresis, heater current, and heater burn-

out alarm can be set.

When pin 1 on the operating mode selector (SW201) is set to the

OFF position (PID action), the temperature setting range limit val-

ues, control period, heater current, and heater burnout alarm value

can be set or changed. Any of these parameters can be selected by

pressing display key the required number of times as follows:

5l-l

Press a.

5l-h

Press a.

Lower/Upper Limits of Temperature Range: sl-l, sl-h

–200

SL–L

Basically, the temperature range that can be measured is deter-

mined by the temperature sensor to be used. For example, when a

K-type (chromel-alumel thermocouple) temperature sensor is se-

lected, the measurable range is from –200°C to 1,300°C. However,

this temperature range can be narrowed, say, to 0°C to 400°C. To do

this, set the lower-limit value of the temperature setting range, in this

case to 0°C, on the SV display by using the up or down key while

5l-l is displayed on the PV display. Similarly, set the upper-limit

value, 400°C, while 5l-h is displayed. If the process temperature

falls below the set lower-limit value or exceeds the set upper-limit

value, it is displayed on the PV display provided it is within the tem-

perature range of the temperature sensor.

Control Period: cp

To use a control period, pin 1 on the operating mode selector

(SW201) must be set to the OFF position. When cp is displayed on

the PV display, the control period can be set or changed in a range

from 1 to 99 seconds in units of 1 second. The factory setting is 20

seconds. When a Voltage Output Unit is used, it is recommended

that the control period be set to 20 seconds or less (ideally, about 2

seconds), so that the control action can be performed more accu-

rately.

Control output

OFF

20 seconds

Lower-limit value of temper-

ature setting range

Upper-limit value of tem-

perature setting range

Control period

Heater current

Heater burnout alarm

400

1,300

SL–H

When control period is

set to 20 seconds

Heater Burnout Alarm: ct, hb

Set a burnout current value to determine disconnections of the heat-

er. Firstly, a current measured in the heater current value mode is

displayed in amperes. The normal current value is the current value

with the control output ON. Disconnect the heater and read the cur-

rent value and obtain the set value from the following:

Normal current value + Current value with disconnected heater

Use display key and set the PV display to hb. The difference be-

tween the normal current and the one with the disconnected heater

should be 2.5 A minimum. If it is less than 2.5 A, the operation to de-

tect the disconnection of the heater may be not stable. The value

can be set with in increments of 0.1 A from 0.0 to 50.0 A.

Note 1: Do not allow a current of more than 50 A to flow in the Con-

troller; the maximum continuous heater current is 50 A.

2: Set the value to 0.0 A if the heater burnout alarm is not used,

in which case the alarm will not function at all.