OM-222166 Page 31
Maximum Temperature Message Screen
Cannot enter Run mode
Programmed temperature settings
exceed air cooled limits
(400
_
F, 204
_
C)
7-5-1-3. PWHT (Post-Weld Heat Treat)
The post-weld heat treat process allows the operator to program a post-weld heat treat where ramp temperature (on increase and decrease) and
ramp rates are the same. When this process is selected, the following screen appears on the display:
Mode......: PWHT
Control TC:>1,2
Ramp Temp.: 200 Ramp Rate: 600
_
/Hr
Soak Temp.: 400 Soak Time: 01:00:00
PWHT Screen
The default position of the cursor is next to Control TC. Press the Increase
or Decrease
button to select the number of control
thermocouples to be used for the program. Selections are as follows: 1, 1,2, 1,2,3, or 1,2,3,4. TC1 MUST always be a control thermocouple. TC2
thru TC4 can be used for controlling or monitoring. When a thermocouple is selected as control, the LED adjacent to the seven-segment display
illuminates.
Use the Cursor
button to move the cursor to the desired selection (Ramp Temperature, Ramp Rate, Soak Temperature, or Soak Time),
and press the Increase
or Decrease
button to change the value to the desired setting.
Figure 6-1. Soak Parameters
Soak Temp
Soak Time
Ramp Rate
Ramp Temp
.
The minimum and maximum ramp temperature settings for PWHT are 0 and 1450
F (−18 and 788
C). The minimum and maximum ramp rates
are 10 and 9999
F/hr (6 and 5555
C/hr). The minimum and maximum soak temperatures are 0 and 1450
F (−18 and 788
C). The minimum
and maximum soak times are 0 and 100 hours or Extended. When the system is utilizing air-cooled blankets, the maximum temperature setting
is 400
F (204
C). If the program setting is above 400
F (204
C), the following screen will appear on the LCD display when the Run button is
pressed.