Table of Contents
Advertisement
Display Shift
In certain applications it is desirable to shift the con-
trollers indicated value from its actual value. This can be
easily accomplished with this control by using the dis-
play shift function. Cycle the control to the
meter by using the "Scroll" pushbutton. The number you
adjust here, either positive or negative, will be the
amount that the process value will be shifted from the
actual value. This amount will be the same across the
entire range of the control. Note the example stated
below.
The desired temperature at the part to be heated is 330
degrees F. In order to achieve that temperature, the
controlled value or the temperature at the sensor must
be 375 degrees F. Due to the design and position of the
components of the system, the sensor could not be
placed any closer to the work.
DISPLAY BEFORE
INPUT SHIFT
Figure 5.7 Display Shift
DIRECTIONS FOR USING RETRANSMISSION (TRANSFER) OUTPUT:
The retransmission output of 4-20mA uses terminals 13 and 14. Terminal 13 is positive (+) and 14 is negative (—).
The interface parameter (Addr) is used to select which value is retransmitted. The possible selections are as follows:
192
Retransmit Process Value, 4-20mA
193
Retransmit Set Point Value, 4-20mA
194
Retransmit Alarm Value 1, 4-20mA
195
Retransmit Alarm Value 2, 4-20mA
Set the span of the control, low scale (Lo.SC) and high scale (hi.SC) to set the span of the retransmitted output.
FOR EXAMPLE: 0-1000, SPAN Lo.SC set to 0 and hi.SC set to 1000 would transmit 4MA AT 0 and 20MA at 1000.
Thermal gradients (different temperatures) are common
and necessary to an extent in any thermal system for
heat to be transferred from one point to another.
para-
The difference between the two temperatures is 45
degrees F. You should input –45 as to subtract 45
degrees from the actual process value.
Cycle the control back to the process value after making
this adjustment.
The display shift will alter the process value only.
The set point must be manually adjusted to 330.
DISPLAY AFTER INPUT SHIFT.
ADJUST SET POINT TO 330
HEAT SOURCE
MOLD
SENSOR
375°F
196
197
198
199
DISPLAY AFTER INPUT SHIFT
AND SET POINT ADJUSTMENT
HEAT TRANSFER
MEDIUM
PART BEING HEATED
OR "WORK" 330°F
Retransmit Process Va,ue, 0-20mA
Retransmit Set Point Value, 0-20mA
Retransmit Alarm Value 1, 0-20mA
Retransmit Alarm Value 2, 0-20mA
Advertisement
Table of Contents
