Series-C I/O modules are constructed to support normal field failures, wiring errors and conditions such as a shorted wire. All Series-C IOTAs contain at least one fuse that provides protection for catastrophic errors in the IOTA, IOM and other elements of the Series-C system. In normal operation as well as many abnormal operations, the fuse element should not blow.
Introduction
An alarm is an indication that an event that you have configured (for example—Process Variable) has
exceeded one or more alarm limits. There are six alarms available, each with two setpoints. You can
configure each of these two setpoints to alarm on various controller parameters. There are two alarm output
selections, high and low. You can configure each setpoint to alarm either high or low. These are called
single alarms. You can also configure the two setpoints to alarm on the same event and to alarm both high
and low. An adjustable hysteresis of 0.0% to 100.0% is configurable for each alarm setpoint.
Priority of functions that operate relays
During alarm conditions an alarm will deenergize its associated relay unless a higher priority function has
been configured for that relay. See Table 3-11. If you want the alarm to control the relay, do not configure
a higher priority function.
Table 4-9 Priority of functions that operate relays
Relay Relay is controlled by (in order of priority)
1 3. Timer function
4. Alarm 1
2 Alarm 2 only
3 5. Controller 1 output algorithms Relay Simplex,
Position Proportional, Relay Duplex,
Current/Relay Duplex
6. Alarm 3
4 7. Controller 1 output algorithms Position
Proportional, Relay Duplex, Current/Relay
Duplex
8. Alarm 4
5 9. Controller 2 output algorithms Relay Simplex,
Position Proportional, Relay Duplex,
Current/Relay Duplex
10. Alarm 5
6 11. Controller 2 output algorithms Position
Proportional, Relay Duplex, Current/Relay
Duplex
12. Alarm 6
