HELIX GRANVILLE-PHILLIPS Convectron ATM, Instruction Manual

Page: 58 / 98

Chapter 4
50
Convectron
®
ATM Vacuum Gauge Module Instruction Manual
Example PC command from host: #1.01E–01
↵
Response from module: *01 PROGM OK
↵
Example PC command from host: #2.00E–01
↵
Response from module: *01 PROGM OK
↵
The “PC1” value identifies process control relay 1.
The “A” (activation) and “D” (deactivation) pressure values determine
activation and deactivation pressures at which the relay switches
states.
• If the “D” value is greater than the “A” value, the relay will always
activate with decreasing pressure and deactivate with increasing
pressure. See Figure 4-6 on page 51.
• If the “A” value is greater than the “D” value, the relay will always
activate with increasing pressure and deactivate with decreasing
pressure. See Figure 4-7 on page 51.
• If you enter equal “A” and “D” values, the module software will
increase the “D” value by the minimum software defined hysteresis.
In default mode, relays 1 and 3 are assigned to the Convectron gauge
and are set to activate with decreasing vacuum chamber pressure and
deactivate at a higher pressure than the activation pressure, as
illustrated in Figure 4-6.
In default mode, relays 2 and 4 are assigned to the differential pressure
sensor and are set to activate with increasing differential pressure and
deactivate at a lower pressure than the activation pressure, as
illustrated in Figure 4-7.
Table 4-9 Relay default activation, range, and hysteresis
Relays Assignment Activation direction Range Hysteresis
Setpoints
1 and 3 Vacuum chamber
pressure Decreasing pressure • Operating range:
1.0 x 10
–4
to 9.99 x 10
2
Torr
• Default setting is out of
range, relay inoperable
Dependent on activation
and deactivation pressures
Setpoints
2 and 4 Differential pressure Increasing pressure • Operating range:
–750 to +125 Torr
• Default setting is out of
range, relay inoperable
Dependent on activation
and deactivation pressures