Lake Shore 372, Руководство пользователя, Страница: 117 / 214

5.1 General 105
|
www.lakeshore.com
Chapter 5: Advanced Operation
5.1 General This chapter provides information on the advanced operation of the Model 372 AC
resistance bridge and temperature controller.
5.2 Zone Settings The Model 372 allows you to establish up to ten custom contiguous temperature
zones where the controller will automatically use pre-programmed values for PID,
heater range, manual output, ramp rate, and relay 1 and 2 states. Zone control can be
active for both control loops at the same time. Configure the zones using 1 as the
lowest to 10 as the highest zone. Zone boundaries are always specified in kelvin (K).
The bottom of the first zone is always 0 K; therefore, only the upper limit is required
for all subsequent zones. Make a copy of FIGURE 5-1 to plan your zones.
To use the programmed zones, the output mode must be set to Zone (refer to
section 4.6.1.4.2 to set up Zone mode). In Zone mode, the instrument will update the
control settings each time the setpoint crosses into a new zone. If you change the
settings manually, the controller will use the new setting while it is in the same zone,
and will update to the programmed zone table settings when the setpoint crosses
into a new zone.
To illustrate how the control parameters are updated in Zone mode, consider the
zone settings in TABLE 5-1. Starting from room temperature (about 300 K), and
setting a setpoint of 2 K (with Setpoint Ramping turned on), the setpoint will begin
ramping at the current setpoint ramp rate, then once the setpoint crosses
100 K, the control parameters from Zone 8 will be used. The setpoint ramp will then
continue toward 2 K at a rate of 20 K/min until crossing 50 K, when the control
parameters from Zone 7 are loaded. This pattern will continue until the final setpoint
value of 2 K is reached, or another setpoint is entered. In this example, the sample
heater is used as the output.
Zone
Lower boundary
(implied)
Upper
boundary
P I D
Manual
output
Range Ramp rate
10 — 0 K 50 20 0 0.0% Off 0.1 K/min
9 — 0 K 50 20 0 0.0% Off 0.1 K/min
8 100.001 K 500 K 200 20 0 0.0% 100 mA 30 K/min
7 50.001 K 100 K 185 25 0 0.0% 31.6 mA 20 K/min
6 25.001 K 50 K 150 30 0 0.0% 10 mA 10 K/min
5 15.001 K 25 K 100 30 0 0.0% 3.16 mA 5 K/min
4 10.001 K 15 K 85 35 0 0.0% 1 mA 2 K/min
3 7.001K 10 K 85 35 0 0.0% 316 µA 0.9 K/min
2 4.001 K 7 K 70 40 0 0.0% 100 µA 0.7 K/min
1 0 K 4 K 50 50 0 0.0 % 31.6 µA 0.5 K/min
TABLE 5-1 Zone settings example