Myron L 729II - Manual (Page 42)

Set Point Conversion (SPC) / Reversing Set Point
The Myron L Company ships the Temperature controller
configured to Alarm/control when the temperature is TOO HIGH. If
the configuration is correct for your requirements skip to
Temperature Set Point Adjust.
As many uses require the temperature to be controlled by the
use of a heater or chiller, the TPO Module may be configured
to maintain an elevated or lowered temperature as required.
To reverse the set point/relay operation:
1. Locate the SPC on TP/TPO circuit board. See figures
III.D.8 & III.D.14.
2. Remove Jumpers.
3. Reinstall Jumpers 90° as shown in figure III.D.15.
FOR TEMPERATURE MODULE
Temperature Set Point Adjust
1. Ensure the SCO Module Set Point control is set
to FULL CCW position. For location see figure III.D.7.
2. Press BOTH the Temperature Select switch and
the Set Point switch on the front panel.
3. Adjust the TP/TPO Module Set Point Two (SP2)
to temperature as desired. See figure III.D.9.
Hysteresis is fixed at ~±6°C unless Special Ordered with
adjustable control.
Hysteresis with adjustable control is variable from ±0.6 to 6°C.
CAUTION: Adjusting the hysteresis too narrow may cause the
alarm to fluctuate (on-off) due to temperature variations causing
the relay to chatter. This condition is to be avoided, it may
damage the heater, chiller, etc. and will eventually damage the
relay.
REASSEMBLY
1. Carefully reinstall the front panel, bottom first.
Ensure no wires have been pinched between
enclosure and front panel.
2. Reinstall the screws and tighten.
3. To operate, turn power ON.
38
Figure III.D.14
FS
INC
INC
TEMP
CONTROL
HARNESS
DETAIL OF SET POINT CONVERSION (SPC)
ON TP/TPO MODULE AS CONFIGURED
WHEN SHIPPED FROM THE MFR.
SET POINT
CONVERSION (SPC)
DEC DEC
SPC
Figure III.D.15
FS
INC
INC
TEMP
CONTROL
HARNESS
SET POINT
CONVERSION (SPC)
DEC DEC
SPC