Lakeshore 336, User Manual

Page: 74 / 192

62 c
HAPTER
4: Operation
Model 336 Temperature Controller
Example 1: A 50
)
, 30 W heater is connected to Output 1.
User Max Current should be set to the smaller of the two or 0.77 A. In this example,
the desired 30 W of power is available to the heater.
Example 2: A 75
)
, 50 W heater is connected to Output 1.
User Max Current should be set to the smaller of the two or 0.66 A. In this example,
only 33 W of the desired 50 W of power is available to the heater.
To enter a User Max Current, first set the Heater Resistance setting to 25
)
for any
resistance less than 50
)
, or to 50
)
for any higher heater resistance. Set the Max Cur-
rent setting to User. The User Max Current setting now becomes available in the Out-
put Setup menu. Enter the calculated current limit value in the User Max Current
parameter.
Menu Navigation:
Output Setup
Q
Output (1 or 2)
Q
User Max Current
Q
(0.1 A to 2 A)
Default:
Output 1
Q
User Max Current
Q
2 A
Output 2
Q
User Max Current
Q
1.414 A
Power Limit Voltage Compliance Limit
I = Squrt(P/R) I = 50 V/R
I = Squrt(30 W/50
)
) I = 50 V/ 50
)
I = 0.77 A I = 1 A
Power Limit Voltage Compliance Limit
I = Squrt(P/R) I = 50 V/R
I = Squrt(50 W/75
)
) I = 50 V/ 75
)
)
I = 0.81 A I = 0.66 A
Heater Resistance
Max Current 10
)
25
)
30
)
40
)
50
)
100
)
2 A 40 W 100 W x x x x
1.667 A (User) 28 W 69.5 W 83 W x x x
1.414 A 20 W 50 W 60 W x x x
1.25 A (User) 15 W 39 W 46 W 62.5 W x x
1 A 10 W 25 W 30 W 40 W 50 W x
0.707 A 5 W 12.5 W 15 W 20 W 25 W x
0.5 A (User) 2.5 W 6 W 7.5 W 10 W 12.5 W 25 W
Shaded black: Max current too high for these resistances due to voltage compliance limit
Lightly shaded: Maximum current/power only available on heater output 1
Bold: Discrete options available for 25
)
and 50
)
heaters under the Max Current setting
TABLE 4-14 User Max Current