Yokogawa EXA DC402 Dual-Channel Conductivity Analyzer User Manual

Page 47

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IM 12D08E02-01E

5-22 Parameter setting

Code 44

*D.TIME

The delay time sets the minimum relay switching time. This function can be

adjusted to give a good alarm function in a noisy process, preventing the

relay from “chattering” or repeatedly switching when the signal is close to the

setpoint.

*SC.HYS The hysteresis is the value beyond the setpoint that the measured value must

exceed before the control function will start working. For conductivity this

setting is expressed in % of programmed setpoint value.

*T.HYST

*C.HYST

Code 45

*RANGE

Proportional range is the value above (or below) the setpoint that generates full

output in proportional control. This is expressed in % of the programmed output

span.

*PER.

The time period of the overall pulse control cycle (one ON and one OFF

period). See fig 5-4.

*FREQ.

The maximum frequency for the pulse frequency control. See fig 5-5.

Code 46

*tI.CNT

The integral time for the PI control settings.

Code 47

*EXPIR

When a system is set up to control on the relay outputs, the expiry time can be

enabled to warn of an ineffective control. In other words, when the setpoint is

exceeded for more than 15 minutes an error message is generated. This can

mean, for example, that the reagent tank is empty.

*tE.min

Code 48

*SC1

For proportional or PI control on the conductivity level, a working range *SC1

must be set. When *SC1 is set as an output on mA1 and *SC2 is set as an

output on mA2, code 48 has no relevance. When using mA1 as mA2 for

calculated values or temperature etc. the range for control setting of the relays

should be done in code 48. After activating code 48 *SC1 is displayed. Press

YES to set range *SC1 or NO to go to *SC2.

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