Electronic Components; Ex Zone 1 - RMG EC 900 Operating Instructions Manual

..........................................................................................................................................................................................................

Electronic components

The EC 900 comprises two boards in each case:
1. The main unit is fixed to the casing cover. It performs the measurement, correction and display
functions. The calibration switch is also located on this board.
2. The connection board inside the casing fulfils the communication functions (for the EC 92x)
among other things. It includes the terminals and batteries. There are two variants: one for
Ex zone 1 (EC 911 and EC 912) and another one for Ex zone 2 (EC 921 with a second battery
and EC 922 with a power pack).

Ex zone 1

Type EC 911
Battery
..........................................................................................................................................................................................................
Pressure transmitter
RS 232 / RS 422 / RS 485
interface
Ex zone 1
CONSTRUCTION AND FUNCTION
< No longer available >
The EC 911 version is exclusively powered by
a lithium battery and has been approved for Ex
zone 1 as an intrinsically safe device.
The EC 911 has two volume pulse inputs (reed
or Wiegand), one encoder input, one tamper
alarm input and six digital outputs.
The device has an optical interface and an
electrical interface. The electrical interface
can be configured as an RS 232, RS 422 or
RS 485 interface using jumpers in the casing.
RS 422 is the default configuration, because
only this interface has Ex approval (see also
pages 20 and 32).
The connection of NAMUR sensors to the
volume inputs VV and VM is not allowed for
the EC 911. The necessary settings for this
purpose are blocked by the software of the
EC 911.
It is possible to upgrade the EC 911 to an
EC 912 without any problem. However, it can
only be converted into an EC 921 or EC 922
after the connection board has been ex-
changed.
5