MSA SUPREMATouch MCP 20, Operating Manual

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188
Redundant Systems
GB
SUPREMATouch
15 Redundant Systems
15.1 Application/Function Safety
For the safety functions of gas warning measuring instruments, the European standards
EN 60 079-29-1, EN 50 104, EN 50 271 and EN 50 402 apply for the monitoring of combustible
gas and vapors as well as oxygen.
Additionally, if systems are using microcomputers, EN 61 508 must be considered regarding func-
tional safety in a measuring and control application.
This standard divides the application types into Safety Integrity Levels SIL 1–4. The system must
be designed to meet the safety level required.
For Safety Integrity Level SIL 3 according to EN 61 508, the SUPREMATouch must be provided
with a redundant power supply. The redundant power supply for the system as well as for the MRC
TS module must have a failure rate of less than 6.73 * 10-6 1/h.
For Safety Integrity Level SIL 4, additional conditions must be met which are not achievable with
the SUPREMATouch.
By adding the MCP module, a second CAN bus and the necessary double modules for data acqui-
sition and setting alarms, the non-redundant system can be converted into a redundant system.
There must be sufficient spare slots in the rack for the additional MGO modules and sufficient
additional space in the cabinet for additional relay modules (MRO).
The following module types are needed for retrofitting:
15.2 Function of Redundant Systems
The block diagram (Fig. 127) of the redundant system shows its design and function:
The signal from the sensors connected to the MAT modules is amplified by 2 separate A/D
converters (on MAI + MAR), the measuring signal is digitised and transferred to the two CAN bus
systems (channels). The signal processing and evaluation of one channel is carried out inde-
pendently from the other. The table “Rack Modules” in chapter 15.3 "Design of the Redundant
System" shows the different components of the rack for a non-redundant and a redundant system.
For module functions, see chapter 11 "Modules".
MCP Module Central Processing
MAI30 Module Analogue Input
MAR Module analogue Redundant
MGO Module General Output
MRO8 Module Relay Output (8 Relay)
MRO16 Module Relay Output (2 x 8 Relay, redundant)